I’m on an inspection on a flipped house, 1958 1400 ft.². The incoming utility lines fit within my number four aluminum wire gauge and I measured the outer sheathing and it measures .328 with my calipers.
The panel is 200 amp disconnect and the utility seal is broken.
I’m looking at my chart that’s been shared on here and it says you need size 2 for 100 amp service. Does this even have 100 amp service or what size would you say this is?
POCOs don’t have to abide by the NEC and do their own thing as they see fit.
Triplex is considered an open air conductor, where it being smaller gauge wire can carry more amps then normal wire.
Agreed.
With that being said, the SEC for the 200 amp main are not 2/0 copper or 4/0 aluminum.
Roger that, so my only concern is what appears to be #2 service entrance wiring feeding a 200 amp panel. So I’m correct in stating that the panel ampacity is 100 amps and refer it out as a defect, correct?
And for those that aren’t experienced with electrical, do not do what I am doing in these pictures and using a metal caliper To measure the wires 
Yes, if the SEC is smaller than what is needed for the breaker and cabinet size, it is the weak link for the service size.
The service point is where the service drop splices to the service entrance conductors (to the right of your hand in photo 1). The NEC starts at the service point so everything ahead of that point is under the utility control and is not subject to the wire ampacities in the NEC.
The conductors after the service point are under the NEC and if the service disconnect is 200 amps then the conductors would need to be sized accordingly.
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David, using metal calipers is dangerous period. The leg is live/hot and does not give you the exact conductor size nor the amount of volts on that leg. As for the PPE you are using. If your hand sweets you will become a conductor. Understanding power distribution at the residential level is means you realize it is deadly, life threating, so I recommend no one use metal calipers on conductors. A true RMS electrical clamp meter is preferred above all others.
You are correct that a #2 AWG service conductor is too small for a 200 amp service.
Regarding the caliper that’s a personal choice. I think that we agree that a metal caliper may not be the best tool for the job unless it is constructed with 1000 volt insulation.
That is not correct. Using metal calipers is not dangerous when used properly, period.
That’s not entirely true. Don’t become a conductor! A sweaty hand alone will not create a path to ground. I’ve held live 120v lines in my bare hand (once, accidentally) and did not get electrocuted because I do not allow my body to create a path to ground when performing electrical work, or inspection work. Albeit, I did feel a small tingle which made me recheck the circuit, oops. A sweaty bird on a single wire does not get electrocuted, why is that
I’ll agree with that.
This has absolutely nothing to do with this post. I was measuring the outer jacket to view the amp rating from a chart to determine proper SE wire gauge. I was NOT measuring amperage!
“So I’m correct in stating that the panel ampacity is 100 amps.” Amperage is ampacity is it not?
NOT.
Ampacity is the maximum allowable current that a wire or electrical component can safely handle.
Amperage is the measurement of how much current is actually flowing at any given moment through a wire or component.
This home in my post had a 200 amp OCPD (disconnect) protecting #2 gauge SE wiring which is undersized. If this wire was copper, it is only rated for 125 amps and if it was aluminum, only 100 amps. This wire may catch fire and burn down the house with a full load well before the OCPD trips. That is why we check wire sizes when inspecting to make sure the maximum allowable current on a wire is not exceeded and has an OCPD that is appropriately sized to not allow more current than the wire can handle.
Spot on description.
My mistake. Please excuse me.
No. Amperage is the amount of electrical current flowing. Ampacity is the current carrying capacity. Rated Ampacity is the amount of current that a system is designed to handle safely. Actual Ampacity is a function of time, current, and operating environment.
I misworded my reply. I think yours is what I was shooting for.
Thanks George. You are always a gentelman.
@dfreund As an aside, where did you buy your plastic wire gauge measuring tool in the op?
I think I want to get one of those for my toolbag.
