Ceramic insulators

I have a inspection coming up this week where the clients sent me a email from the realtor. The agent said, the panel and most wiring looks updated. The outside stack and brown insulators are old and might be drawing 100 amps through a feed that was intended for 60 amps? Any thoughts?

You never know until you get there.

Thanks. In my area from the street to the home is owned by the town and always 100 amp minimum. I think their concern are the ceramic insulators being correct.

Are you saying that the wire to the main service panel from the street is only 60 amp wire?

That is typical of a Service Equipment replacement that was done without a permit. In most jurisdictions which have electrical code enforcement the power utility will not upgrade a service drop or lateral until they receive clearance to do so from the Authority Having Jurisdiction. When the Service Equipment is replaced without a permit that never happens. There are several clues that might be present if that is what happened. If the meter enclosure is tiny compared to other homes that you have seen in that utility’s service area that have a main breaker that is the size of the one in the home that you are inspecting that is strong evidence. If the Service Entry cable looks small in comparison to other services of that ampacity, the service drop is open wire rather than triplex, or the date on the meter seal is obviously prior to the age of the Service Equipment then those would be additional indicators. The problem with that last one is that the seal may have been removed so that the installer could pull the meter to de-energize the Service Equipment to do the work. If there is no seal at all then that is a pretty good clue. That is affected by the serving utility’s practices. Many utilities reseal any meter that the meter reader finds unsealed without investigating further. The utility’s concern is power theft rather than non-permitted work. I have seen inspectors use a gauge that identifies the actual size of the service entry cable. That size is a very strong indicator of the ampacity of the service that it fed when it was installed. The town may have accessible records that would allow you to check when the last permit was issued for the property. The date of any service upgrade permit should be consistent with the age of the service equipment.


Tom Horne
Retired Electrician.

There always 100 Amperes now. What was the minimum size of a residential service when that home was built?


Tom Horne
Retired Electrician

Thanks for the feedback. Haven’t been to the house yet but it will be 100 amp going to the house. I have seen where the old stack and brown insulators haven’t been changed with a new 100 amp panel in the basement and 100 coming from the street. The agent told the buyers that since they weren’t changed it might be drawing 100 amps through a feed that was intended for 60 amps?