Past technical recommendations such as IEC/TR as well as newer specifications such as IEC/TS are both used by power utilities for insulator selection in polluted outdoor environments.
This edited contribution to INMR by Dr. Wallace Vosloo, retired from Eskom, Richardo Davey of Eskom Research Testing and Johannes Bekker at the University of Stellenbosch in South Africa reviewed different possible approaches in this regard.
Selecting porcelain and glass insulators for three-phase a.c. systems up to 525 kV phase-to-phase using IEC/TR (Guide for the selection of insulators in respect of polluted conditions) has been based on service experience as well as laboratory testing under naturally and artificially polluted conditions. As stated in this document: Simple general rules should assist choosing the insulator, which should give satisfactory performance under polluted conditions.
Fig. 2 and Table 2 summarize basic profiling rules recommended in IEC/TR , which are normally followed.
Influence of insulator diameter on pollution performance is also considered for insulators with average diameters of between 300 and 500 mm. In the case of diameters greater than 500 mm, it is recommended that specific creepage distances be increased by 10% and 20%. Laboratory tests, in accordance with IEC 507, are also recommended to evaluate an insulator’s pollution performance but are rarely used by most power utilities. Greasing or washing is recommended for areas with severe pollution and/or low natural washing.
For a.c. porcelain and glass insulators, a utility would typically specify maximum connection length taking into account live line work, minimum dry arcing distance, and minimum creepage distance. Then, it would be stated that insulator profile must comply with IEC/TR , the focus being on simplicity and ease of use.
It is proposed to erect 132 kV lines in areas with pollution levels ranging from Light to Very Heavy using standard glass cap & pin disc insulators (U120B, F12/146). Assuming the parameters given below, how many discs (n) would be required per string?
System highest voltage (Um) = 145 kV
Minimum required Dry Arcing Distance (DAD) of the insulator string is mm (i.e. for a high lightning area)
Disc spacing (s) = 146 mm
Arcing distance per disc (a) = 210 mm
Creepage distance (CD) per disc = 320 mm
The arcing distance of a disc insulator string = a + (n – 1) s
Thus, = 210 + (n – 1) x 146 and n = ( – 210) / 146 + 1 = 9.84 (in other words, 10 discs are required)
In terms of pollution level, as shown in Table 1, the specific creepage distances needed for Light, Medium, Heavy and Very Heavy pollution areas are 16, 20, 25 and 31 mm/kV (Um) respectively.
Number of discs required per string = (CD)/320 where CD = (Um x SCD)
Table 3 gives values calculated using (145 x SCD)/320.
Utilities have typically been using 7 to 14 standard glass discs per string for 132 kV lines. More recently, with the advent of new ‘active’ polymeric insulation materials that interact with the environment, utilities have continued to use IEC/TR since nothing else was available in IEC.
Typically, for a.c. polymer insulators, utilities such as Eskom would specify maximum connecting length (taking into account live line work), minimum dry arcing distance and minimum creepage distance. They would also state that insulator profile must:
1. comply with IEC/TR based on in-service and test station experience;
2. have open aerodynamic alternating shed profile with S/P ratio ≥ 1; and
3. that the material must be hydrophobic, with good hydrophobicity transfer capabilities.
Then, for e.g. ease of stock, minimum SCDs of 20 mm/kV for Light to Medium and 31 mm/kV for Heavy to Very Heavy pollution areas would be specified.
Insulation requirements for both UHV a.c. and d.c. insulators are more complex and normally determined along with technical experts from manufacturers (mostly members of Cigré WGs).
The following major changes have been made with respect to IEC/TR :
• Encouraging use of site pollution severity measurements, preferably over at least a year, in order to classify a site instead of the previous qualitative assessment (see below).
• Recognition that ‘solid’ pollution on insulators has two components: one soluble and quantified by ESDD; the other insoluble and quantified by NSDD.
• Recognition that, in some cases, measuring layer conductivity should be used for SPS determination.
• Using results of natural and artificial pollution tests to help with dimensioning and to gain more experience in order to promote future studies to establish a correlation between site and laboratory severities.
• Recognition that creepage length is not always the sole determining parameter.
• Recognizing the influence of other geometry parameters and of the varying importance of parameters according to the size, type and material of insulators.
• Recognition of the varying importance of parameters according to type of pollution.
• Adoption of correction factors to attempt to take into account influence of the above pollution and insulator parameters.
Fig. 3 shows three approaches proposed for selection and dimensioning of insulators.
Fig. 4 provides Eskom’s specifications for determining site pollution severity and pollution performance curves.
It has been proposed to erect a 132 kV substation and interconnecting lines at Koeberg Nuclear Power Station (KNPS) along the South African west coast. The area is approximately 600 m from the coastal high-water mark and is exposed to strong coastal winds, low rainfall and regular salt fog events. The insulators (substation: 189 – posts (4 kN), 294 – hollow cores (average diameter
The question is what insulation is required to ensure risk of insulator flashover is minimal, with mean time between flashover (MTBF) of at least 50 years?
Approach 1: Use Past Experience
Duinefontein 132 kV Substation (≈600 m from the coastal high-water mark) is situated only ≈1 km from the new proposed 132 kV substation and interconnecting lines area at KNPS.
In , the 60 porcelain station post insulators installed at the Duinefontein Substation that have a specific creepage distance of 32.4 mm/kV were upgraded (along with all other insulation) using room temperature vulcanized silicone rubber coating (RTV SR A). Prior to this upgrade (since washing did not work and greasing had only a 6 to 12 month effective lifespan) the substation experienced flashovers on an annual basis, including the Type B instantaneous event of February . Since the upgrade, no flashovers occurred to date (18 years later), which includes the catastrophic Type B instantaneous pollution event experienced in February . Indeed, the RTV SR A coating still has excellent hydrophobic properties.
Personnel from the KNPS Weather Station (≈250 m from Duinefontein Substation) classify the area as follows:
• Average ambient temperatures between 14° and 20°C (minimum 4°C and maximum 36°C);
• Exposed to strong coastal winds (gusts up to 35 m/s);
• Low rainfall area (≈320 mm per year) with only 3 to 5 rainy days in summer (≈80 mm)
• High humidity levels at night/early morning and regular salt fog events (≈40 per year).
ESDD, NSDD and DDDG pollution measurements at the Duinefontein Substation from March to date, were used to calculate ESDD2% = 0.165 mg/cm2 (STDEV = 0.57), average ratio of NSDD/ESDD = 1.1 and monthly average DDDGave = 382 µS/cm.
The flashover of a bare porcelain 132 kV breaker support insulator (having specific creepage distance 32.4 mm/kV) during the catastrophic Type B instantaneous pollution event experienced in the Cape in Feb was used to estimate minimum uniform pollution present on insulation during this event, namely ESDD = 0.4 mg/cm2 and NSDD = 0.182 mg/cm2. Field experience has shown that, while instantaneous pollution events will not occur annually, it can be conservatively assumed that one event occurs each year.
Pollution levels at Duinefontein Substation are as follows:
Type A: 40 natural pre-deposited pollution events per year with critical wetting (ESDD2% = 0.165 mg/cm2 with STD deviation of 0.57 and ESDD/NSDD ratio = 1.1).
Type B: One instantaneous conductive fog pollution event per year (ESDD2% = 0.4 mg/cm2 and NSDD = 0.182 mg/cm2).
The SPS levels obtained from ESDD and NSDD measurements at Duinefontein Substation (see Fig 5) classify the area for Type A pollution (E6/7) d – Heavy and Type B (E7) e – Very Heavy. DDDG measurements, after climatic factor correction, classify the area as Very Heavy.
The 60 RTV SR A coated porcelain station post insulators with SCD of 32.4 mm/kV at Duinefontein Substation (≈1 km from the new proposed 132 kV substation and lines area) have provided excellent performance for 18 years. Note: these same 60 bare porcelain station post insulators had flashed over more than once annually. No washing or greasing was recommended.
Koeberg Insulator Pollution Test Station (KIPTS) (≈50 m from the coastal high-water mark) lies about 2 km from the new proposed 132 kV substation and lines area. Monthly average DDDGave = µS/cm measured at KIPTS is Extreme (≈6.6 times higher compared to Duinefontein Substation). Findings of some insulator research and tests done at KIPTS over 15 years are presented in “Power Utility Perspective on Natural Ageing and Pollution Performance Insulator Test Stations”.
From natural insulator pollution performance experience gained at KIPTS the following:
Posts: Porcelain post insulators with SCD = 38 mm/kV will flashover more than 3 times per year at KIPTS;
RTV SR A coated porcelain post insulators with SCD ≥ 24 mm/kV will have no flashovers per year at KIPTS. RTV SR A coated porcelain transformer bushings at KIPTS with SCD = 30 mm/kV will perform well for 15 years;
Open aerodynamic alternating shed profile with S/P ratio ≥ 1 and a hydrophobic material with good hydrophobicity transfer capability will work best.
Hollows: SR hollow core insulators with SCD ≥ 28 mm/kV will have no flashovers per year at KIPTS;
Open aerodynamic alternating shed profile with S/P ratio ≥ 1 and hydrophobic material with a good hydrophobicity transfer capability will work best.
Longrods: SR longrod insulators with SCD ≥ 22 mm/kV will have no flashovers per year at KIPTS;
Open aerodynamic alternating shed profile with S/P ratio ≥ 1 and hydrophobic material with a good hydrophobicity transfer capability will work best.
Note: Corona rings should be installed on 132 kV longrod insulators.
Strings: Standard glass cap & pin disc insulator (F12/146) strings with SCD of 27 mm/kV will flashover more than 3 times per year at KIPTS. The same insulator string with RTV SR A coating applied will have no flashovers per year;
Fog-type glass cap & pin disc insulator (F120P/146) strings with SCD of 37 mm/kV will have no flashovers per year at KIPTS. The same insulator string with RTV SR C coating applied will experience similar leakage currents to SR longrod insulators.
Note: Expect poor natural washing/cleaning and pin erosion problems.
Approach 2 (as per Fig. 3) is used along with Section 12 of IEC/TS -2 for porcelain and glass, and Section 12 of IEC/TS -3 for polymeric insulators.
The pollution and climate at Duinefontein Substation (as in Approach 1) give the expected pollution severity levels and climate in the area of the proposed 132 kV substation and interconnecting 132 kV lines as follows:
Type A: (E6/7) d – Heavy as 40 natural pre-deposited pollution events per year with critical wetting (ESDD2% = 0.165 mg/cm2 with STD deviation of 0.57 and ESDD/NSDD ratio = 1.1).
Type B: (E7) e – Very Heavy as one instantaneous conductive fog pollution event per year (ESDD2% = 0.4 mg/cm2 and NSDD = 0.182 mg/cm2).
Candidate insulators were selected as shown in Table 4, where possible with a maximum connecting length of 1.48 ± 0.02 m, minimum insulation length of 1.2 m, minimum dry arcing distance of 1.5 m, minimum specific creepage distance of 31 mm/kV (CD ≥ mm). Insulators with open aerodynamic alternating shed profile with S/P ratio ≥ 1, and hydrophobic material with good hydrophobicity transfer capabilities. Porcelain post, standard glass and fog type glass insulators were included as reference.
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Laboratory pollution U50% flashover voltage (using the rapid flashover test method) curves at three pollution levels (as in Fig. 4) – SDD of 0.06; 0.12 and 0.48 mg/cm2 with NSDD ≥ 0.1 mg/cm2 was obtained using:
• for porcelain and glass insulators the Solid Layer Test Method (see Table 5) according to IEC using Procedure B and spray gun for applying the Kaolin composition and Annex B.3.2. The degree of pollution on the test insulator was determined using the SDD method. Recommendations as given in Annex D and E were followed.
• and, for polymeric insulators according to modified Solid Layer Test Method (see Table 5) with pre-conditioning procedure, and with/without recovery according to Cigre TB 555 and Cigre TB 691.
The rapid flashover laboratory solid layer pollution test done on SR Longrod A insulator to determine U50% = 225 kV at SDD = 0.12 mg/cm2 and NSDD = 0.1 mg/cm2 with 48-hour hydrophobicity recovery is shown in Figure 6 as example. The rapid flashover laboratory solid layer pollution test results for all the candidate insulators are shown in Table 4.
The candidate insulators’ pollution U50% flashover voltage results in Table 4 were then converted into flashover stress along the test insulation length HT = 1.2 m as in kV/m and is presented as a three-point approximated inverse power law curves against pollution level SDD in mg/cm2 in Fig. 7.
The candidate insulator pollution flashover performance curve constants A in kV/m and α was determined for equation U50%/Ht = A · SDD-α and the values are shown in Table 4.
Um-ph/H was calculated as 70 kV/m using the specified insulation length H = 1.2 m, and Um-ph = 83.7 kV (the highest system r.m.s. phase to ground voltage that the insulator to be supplied will be subjected to).
The candidate insulator was accepted for further calculation if U50%/Ht> 70 kV/m in the SDD range of 0.12 to 0.48 mg/cm2.
Insulator pollution flashover performance curve constants A in kV/m and α, of the candidate insulators was used along with pollution severity levels and climate in the area of the proposed 132 kV substation and interconnecting 132 kV lines in the statistical approach as per Annex G of IEC/TS -1 in order to optimize insulation selection. Fig. 8 shows the Insulator Selection Tool, a commercially available statistical software.
As example, using the IST for MTBF of 50 years 768 – 132 kV SR Longrod A insulators require:
• SCD of 20.2 mm/kV when exposed to 40 natural Type A pre-deposited pollution events per year with critical wetting (ESDD2%= 0.165 mg/cm2 with STD deviation of 0.57 and ESDD/NSDD ratio = 1.1) (see Fig. 9);
• and SCD of 22 mm/kV when exposed to one Type B instantaneous conductive fog pollution event per year (ESDD2%= 0.4 mg/cm2 and NSDD = 0.182 mg/cm2) (see Fig. 10).
The MTBF obtainable within the required connecting length of 1.48 ± 0.02 m and SCD needed for MTBF of 50 years was calculated for the reference and candidate insulators using the IST. Results are shown in Table 6.
Approach 3: Measure & Design
As per Fig. 5, the area proposed for the 132 kV substation and interconnecting lines can be classified for Type A pollution as Class d – Heavy and for Type B pollution as Class e – Very Heavy. Thus, in the worst case, a minimum SCD of 31 mm/kV is needed for the reference glass disc insulator.
As per IEC/TS -2, the following is recommended for porcelain and glass insulators:
• Aerodynamic, alternating sheds on long rod insulators, post insulators, hollow core insulators;
• Anti-fog profile for disc insulators;
• p1 – p2 ≥ 15 mm, s/p ≥ 0.65, c ≥ 25 mm, l/d ≤ 5, 5˚ ≤ α ≤ 25˚ and CF ≤ 4 (lowest risk options used);
• No altitude correction required;
• 10% increase in SCD for hollow core insulators with average diameter > 300 mm and
As per IEC/TS -3, the following is recommended for hydrophobicity transfer polymeric insulators:
• SCD could be reduced or increased depending on the environment or pollution level (no clear advice given);
• Aerodynamic alternating sheds;
• p1 – p2 ≥ 18 mm, s/p ≥ 0.75, c ≥ 40 mm, l/d ≤ 4.5, 5˚ ≤ α ≤ 25˚ and CF ≤ 4 (lowest risk options used);
• No altitude correction required;
• 10% increase in SCD for hollow core insulators with average diameter > 300 mm and
Insulators must have a minimum SCD of 31 mm/kV (CD = mm) and hollow core insulators with minimum SCD of 31 x 1.1 = 34.1 mm/kV (CD = mm) are recommended. Table 7 provides a summary and comparison of results obtained for these three Approaches.
As per Table 7, the findings of Approach 1 and 2 correlate with one another, showing that both approaches would work if correct data required as per Fig. 3 is available. The practical examples demonstrate that both approaches lead to a selection having good accuracy. Moreover, as per Table 7, Approach 3 in general would result in over-dimensioning of required insulation.
Table 8 offers a comparison of the recommendations as per IEC/TR and specifications as per Approach 3 in IEC/TS -1 for the practical examples. Findings are similar in regard to specific creepage distance. However, Approach 3 takes into account use of hydrophobicity transfer materials, which could result in a one class lower SCD, different profile parameters and anti-fog instead of open aerodynamic disc insulators.
In summary it has been demonstrated with practical examples, how the old technical recommendation, i.e., IEC/TR and the new technical specification i.e., IEC/TS are being successfully applied by a utility, in this case, Eskom, to select and dimension outdoor insulators for polluted environments (Note: Ageing and failure modes are not taken into consideration in this discussion).
The importance is also shown of site pollution severity measurements, climatic conditions, identifying pollution type and practical use of data collected from natural pollution test sites, in-service insulators, laboratory pollution flashover tests and statistical evaluation.
The "Ten Tips" listed below are suggestions for new insulator collectors, based upon my own experiences. Some of them could have a whole page devoted to them, but rather than do that, I have attempted to be brief and give you just enough to convey the idea. The Case Study is factual, and serves to illustrate the importance of some of my advice.
Several years ago I noticed a classified advertisement in my local newspaper about an insulator collection for sale. I contacted the seller on the , and made arrangements to see him and his collection. My goal was to buy the collection if it was a decent one, as I was a relatively new collector at the time, anxious to expand my own collection. The below are the salient details of my visit and observations:
My impression was that the seller needed to sell his collection because he and his wife had recently purchased a new house, and needed the money to finish the yard – landscaping, fences, etc. Although he was personable, I tactfully declined to buy the collection. About six weeks later I was again reading the classified ads, looking for insulators to buy. I saw an interesting ad and called the number in it. It turned out to be the same seller – I hadn’t recognized his number, and he still hadn’t sold his collection.
New collectors should try to find a more experienced collector, and then use that collector as a mentor. Most of us are flattered by someone asking questions about a subject that we know something about. Don’t be bashful about telephoning a collector and inviting yourself over after you’ve explained that you’re a new collector -- insulator collectors are some of the most friendly and generous people that you’ll ever meet. Preferably, your mentor should be a local collector so that the two of you can occasionally visit each other. The experienced collector can offer advice in the form of education, and advice about what pitfalls to avoid. When I was a new collector, I was fortunate to have several established collectors to buy insulators from at attractive prices, to volunteer general information and advice, and to answer questions.
Secondly, insulator collectors are almost always pleased to have someone take an interest in their hobby – few people do, including their ‘significant others’. Therefore do not be surprised if your potential mentor wants to show his/her collection to you – use the opportunity to ask questions and acquire knowledge about insulator collecting. Pick the brains of the collector, with the goal of learning as much about insulator collecting as he/she does. And remember that ‘no question is a stupid question’, and ‘if you ain’t asking, you ain’t learning’.
Insulator collecting is a highly organized and detailed hobby, with its own terminology, identification systems, price guides, history and practices. Therefore you must possess a certain amount of knowledge for you to know what it is that you’re collecting, to assist you in collecting, and to communicate knowledgeably with other collectors. To be able to do that, you have to acquire the reference books applicable to that portion of insulator collecting (glass or porcelain) that you’re interested in. You’ll find that after a short period they’ve become invaluable tools that have paid for themselves. Some common examples illustrate why you need the reference books:
Regard your collection as an asset that will appreciate in value over time. Whether insulators will appreciate in value and be investments is debatable, and I’m not suggesting that will happen – I honestly don’t know. But you should acquire insulators with the view that you may want to sell or trade them in the future, and hopefully recover most of your acquisition costs if you do. Therefore buy the best insulators that your budget can afford, particularly with respect to their physical condition. Most insulator are not ‘mint’ and we all have to have some damaged insulators in our collections (e.g. I have yet to see a CD 196 insulator for sale/trade that was in good physical condition). But establish a standard of acceptable physical condition for your collection and budget, and then stick with it. Many collectors will buy damaged insulators and then ‘upgrade’ them in the future when the opportunity arises. If you do the same, pay a price for that first insulator that is commensurate with the damages.
With the recent parcel rate increases by the American and Canadian post offices, shipping costs are becoming a significant portion of insulator acquisition costs. Because insulator collectors reside all over North America, with a few overseas, insulator acquisition frequently requires that they be sent by mail or commercial courier. When you’re buying or trading for insulators that have to be shipped to you, keep in mind that the first one in a parcel is the most expensive to ship, and the last one is the cheapest. This is because of the way that the parcel rates are structured – the last weight increment is the cheapest. While this may sound like common knowledge, I still come across collectors who buy one or two cheap insulators at a time, and then have the postage to send them equal or surpass their value. This is important, because the convention is that the buyer pays for the shipping costs. I recently quoted a collector $4.48 for postage costs to send the one small insulator that he was interested in. But to send him a parcel of four insulators, the postage costs were only $7.82 – obviously ‘more is better’ to lower average shipping costs.
Therefore if you’re acquiring insulators where you have to pay the shipping costs, buy a sufficient quantity to minimize your average shipping costs. To do that, try to patronize those sellers that are selling at least a couple of insulators that you want to acquire – try to get the biggest bang for your shipping dollar. Avoid buying from sellers that only have one insulator of interest to you. Of course, there will be times when that is not always possible because other considerations will over-ride the economics. An example might be that you’ve finally found a scarce insulator that has been difficult to acquire in the past, and it could be a long time before it becomes available again.
The current price guide for North American glass insulators cites over 9,000 different insulators – different because of the different combinations of CD numbers, colors, primary embossings, and specific embossings. Granted, the differences between some are subtle (e.g. the difference between two specific embossings might only be one having periods after abbreviations, and the other one doesn’t). But if we include the differences that the price guide doesn’t address, such as the different variations in the color ‘aqua’, then the number becomes larger. And then if we include foreign glass insulators, porcelain insulators, and insulator related items (radio strains, guy wire strains, dead-end spools, knobs, etc.) we’ve got a huge number that is not yet known.
My point here is that no collector has the time and money to acquire all insulators, and the space to display or store them. Therefore I suggest that after you’ve acquired enough information about insulators to know roughly what there is out there to collect, start to consider specializing. There are many ways to specialize, so I won’t get into them in this brief article – just establish some collecting criteria once you know what appeals to you the most. Not all collectors specialize – many just acquire insulators that appeal to them, and there’s nothing wrong with that – instead of a collection that has a theme, their collections are eclectic. But the advantage of specializing is that it functions as a screening process for insulators that are outside of your collecting criteria. There is no shortage of insulators to acquire, and it’s tempting to acquire many of them -- but if they are not within your specialty, resist temptation and use your money or traders to acquire those that are.
It is important that you communicate with other insulator collectors. I have met a few insulator collectors who have been collecting in isolation, and it’s been a frustrating experience for both of us. From my perspective, they have no knowledge about the hobby -- supply sources, contacts, new developments, current prices, and terminology. The above Case Study is about such a collector. The advantages of communicating with other collectors are the following:
You can be part of the insulator collecting community by any one of the following:
When I was a new collector there were several occasions when I purchased insulators from antique shops and flea markets, only to find out later that they were duplicates of what I already owned – I couldn’t remember what I already had in my collection. I then made a computerized inventory of my collection, and took a hard copy of it whenever I knew that I would be insulator shopping. I won’t go into a lot of details, because there is an excellent article written by Bill Meier about cataloging your insulator collection. If you don’t have a personal computer, you can still catalog your collection the old fashioned way – I recommend using a columnar pad purchased from a stationary store.
I strongly recommend an inventory if your collection is 100 or more insulators. My own inventory consists of one spreadsheet for each of my 14 ‘sub-collections’, the total of all of them being about insulators. At a glance, I can determine if I already own a certain insulator when I see a similar one for sale, and if I do, whether I need an upgrade for it or not. I also compare the total acquisition costs of my collection to the total Price Guide values to determine if my total acquisition costs are reasonable or not.
Besides allowing you to know what your collection consists of, an inventory is also advisable for insurance purposes. As an example, if your collection eventually grew to be worth $5,000 (very easy to do) and you then had a house fire or vandalism, the inventory would be invaluable in helping you file an insurance claim. For that reason, you should keep a recent copy of your inventory with your other valuable papers in your safety deposit box.
Like so many other items and activities, the sky’s the limit with respect to the amount of money that can be spent on insulators – prices range from free to thousands of dollars. Therefore it is important that you establish financial limits that are reasonable for your disposable income, and then stay within those guidelines. Ask yourself if your insulator collecting costs are in addition to, or in place of your other recreational expenses. If the costs are in addition to your current hobby and recreational expenses, can you afford insulators?
I am aware of a few collectors that became so enthusiastic about insulator collecting that they forgot about financial common sense, and eventually suffered the consequences. You don’t have to be rich to be an insulator collector – most insulators are priced below $20, and it is possible to build a very respectable collection on a limited budget over time. Trading with other collectors, and buying from flea markets, garage sales and second hand stores will also reduce your cash outlay. Remember that insulator collecting is supposed to be an enjoyable hobby, and not the cause of financial stress.
Most antique stores/shops have a few insulators for sale, and a lot of insulators are actually ‘antiques’ by virtue of being over 100 years old (although many antique dealers have a much more liberal definition of that term). In my area, it is not uncommon to find a $0.50 insulator with a $10.00 or more price tag on it – and it is frequently so damaged that I would throw it away. To be fair to those antique dealers, they have overhead costs that they have to recover, whereas the suggested prices in the price guides are for transactions between collectors who do not have the same costs.
Antique dealers know very little about insulators, nor can they be expected to – their inventory is too vast for them to concentrate on every type of antique. Therefore antique dealers know a little bit about a lot of antiques, but their depth of knowledge about any one of them is very superficial. So beware of misinformation from them – I once had an antique dealer tell me that a Dominion CD 154 was made in because the embossing said ‘DOMINION - 42’. Because insulators are not a big money maker for them, antique dealers don’t spend the time to learn more about them – it just wouldn’t be cost effective. For that reason, occasional bargains can be found in antique stores if you know your insulators and prices well enough – the antique dealer’s price is low relative to that suggested by the price guide.
This tip was suggested by my wife, and after thinking about it, it’s excellent advice. If you have a ‘significant other’ in your life, it’s important that approval for your insulator collecting be given by that person. And the more serious you are about insulator collecting and the more resources that you give to it, the more important that approval becomes. When I initially informed my wife that I was going to collect insulators, she thought that I was joking. And then she started to resent my hobby because of the amount of time that I was devoting to it, and not to activities that the two of us could be doing together. We ended up having many ‘discussions’ about my hobby. And I had to buy a second personal computer for her to use because I was monopolizing our first one, doing insulator related things with it.
Insulator collecting requires time, money and space – not just to acquire and display your insulators, but for related items and activities as well (e.g. reference books, attending swap meets). Therefore make sure that your significant other is in agreement with your hobby -- involve him/her if they’re willing to participate. But don’t let insulator collecting become a source of friction between the two of you – it’s supposed to be a stress reducing hobby!
I have a hard time visualizing insulator collecting prior to personal computers – I know that it was done, but it must have been very time consuming, expensive and laborious. If you don’t already own a personal computer, then insulator collecting is another reason to get one. And if you already have a personal computer, which you probably do if you’re reading this, then use it as tool to assist you with your collection.
I have already mentioned Bill Meier's article about using a computer to catalog your collection. Another major computer use is communication with other collectors. Prior to getting capability, my long distance costs were frequently in excess of $100 per month because of calls to other collectors. Now I rarely call anyone long distance, and then only if I’m calling a person that doesn’t have an address. I buy, sell and trade insulators by and the Internet. I subscribe to the ICON news/chat line, and periodically visit the Glass and Porcelain Insulator Web Site and its links to see what’s new in the hobby. Other insulator related uses for my computer are correspondence, making parcel shipping labels, record keeping and digital photography.
Last updated Thursday, February 4,
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