Today’s inspection had what looked like a 125 - 150 amp service feed connected to what looked like 4.0 wiring and a 200 amp main disconnect. Is this right? My thinking is that it would be hard pressed to trip the 200 amp main.
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If that is the feeder from the power company, then what they do is OK.
A few other issues though!
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The utility service line follows a different standard because they are always open-to-the-air, ensuring that heat is rapidly dissipated. Your real concern is the lack of clearance from the building and, in particular, direct contact with the metal downspout.
Yeah, I noted the distance to the building and the possibility of energizing the roof drainage system. I just didn’t know about the different wiring sizes. I guess that since it’s on the other side of the meter it’s not necessarily the homeowners concern.
Many years ago, I called up the utility over a similar concern. I learned that the utility company has a code exception to size the service drop however they deem appropriate.
The weatherhead on the SE cable is missing. Nothing wrong with whatever size drop conductors the POCO uses upstream of the service point.
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Utility companies don’t need a code exception. They are governed by state tariffs in the US. It may be different in Canada.
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I concur, George, but the PoCo overhead service cables requires proper clearance.
The SEC cables are clearly contacting the aluminum downspout. Wouldn’t it be within their jurisdiction to fix it?
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Thanks. The utility used the “exception” word with me.
The short answer to your question is, maybe, or maybe not. It varies among utility companies. The utility company that provided service where I did the majority of my electrical work as an electrical contractor was responsible, at that time, for everything up to the point where the service conductors attached to the SEC in a residential building. Everything after the point of connection was the homeowner’s responsibility.
The local utility company later merged with another Ohio utility company and changed their rules. At that time, I was no longer working as an electrical contractor. I was working as an engineer and project manager on commercial and industrial projects. I also taught continuing education though, so I stayed current with the local residential standards.
The homeowner was now responsible for everything up to the supply transformer under the new rules. The utility company would do the installation and maintenance work, but it was only upon request and it was for a fee. They were not obliged to do anything past the supply transformer. If they were busy or just didn’t want to do the work, it was the homeowner’s responsibility to hire someone who would do the work.
However, the utility company maintained the right to decide what they would or would not connect to. Everything up to, and including, the service panel had to meet their specifications. The local inspection authority did the inspection of everything from the point of connection. That was by mutual agreement between the two entities. The utility company would inspect everything on the outside after the local building authority approved the installation. If it didn’t meet with their approval, they wouldn’t connect to it.
In Ohio, tariffs are negotiated individually between the public utility commission and each public utility company. The important thing to understand is that the tariff is what governs a utility. If they adhere to any particular model code, it is either because they simply chose to or it is in their tariff. I have never seen a tariff that mandates following any model code. Most utility companies, however, will voluntarily follow the NESC to some extent, and the NEC to a some extent.
I have negotiated enough contracts between enough utility companies and large customers that I have a good working knowledge of what is in most utility company tariffs. The tariffs establish, among other things, what utility companies can charge. That ultimately affects the consumers of energy, hence the depth of my involvement.
You have long heard me preach to home inspectors the importance of knowing the local standards and requirements. The local utility company is one of the best, if not the best, sources of that essential information.
I have never worked with a Canadian utility company. What they do in Canada may be very different from the US. My advice remains the same though. In my home inspection classes, I make that recommendation and I ask attendees where they are from. Based on where inspectors work, I have gone online to see if their local utility company has their standards and specifications online. Every utility company I’ve checked has had the information available for download. A few of them have had websites that weren’t well organized and it took a little time to find the information, but it has been there every time.
Tariffs are also available to the public. They are the blueprint for how a utility company operates, how much it can charge for energy and services, its rights, and its duties and obligations. In the US, the tariffs are available through both the utility companies and the public utility commissions.
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Thank you for the information, George.
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#4AWG aluminum Tri-Plex is common coming from a standard 25kVA transformer. The transformer is not typically fused on the secondary. It is fused on the primary. The typical fuse Amperage rating on the primary is 3.5-5A. The transformer secondary current rating is approximately 104A so #4 aluminum in free air is adequate.
All electrical equipment ratings in the US are extremely conservative. That’s why they are so inherently safe. Transformer failures resulting from non-fault overloads are rare. Service drop conductor failures from non-fault overloads are even more rare.
A single 25kVA transformer will serve one to seven houses, with 3-4 being common. Therefore, the transformer would likely be overloaded before the service drop conductors. That means even a #4 is usually bigger than is needed. As you can see, utility companies are much less conservative than the NEC. Electrical fires resulting from non-fault overloading of electrical systems in the US are rare.
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