Conductor Size

I have a new home with 2 service panels. One is on a 150 amp breaker with 2/0 Aluminum wire and the other is a 200 amp breaker with 2/0 aluminum wire. Can 2/0 aluminum be sufficient for 200 amps if the distance is short.

Look at the attachment.

I appreciate that and I do have a similar table. The issue I have is that the wire from the meter to the breaker is 2/0 aluminum and the breaker is 200 amps but it is a very short length. Not sure if it is an eye trick or not but the wire from the breaker to the distribution panel looks 2/0 but the label is not visible. In a short stretch is it ok to have 2/0 aluminum. The house is only 2 years old and I don’t want to make a big mess out of nothing.

Here’s an up close of the breaker. The upstream wires from the meter are 2/0 aluminum. Not sure if that is ok. But also curious if the other wires that are downstream look 2/0 or 4/0.

The answer to your question, underlined above, is no.

Does the wire on the left side with the red stripe look like the same size or could this be a 4/0 wire?

I can’t tell from Michigan. I wasn’t standing in front of the panel. And my eyes aren’t what they used to be…:slight_smile:

For 200 amps in this application you would need #4/0 Aluminum conductors.

That’s what I thought. Thank you.

Matthew you have 2/0 awg wire, 67.43 mm2 = 2/0 AWG per the wire sheathing. Just defer per what you see. If sparky says its ok, then so be it vs you having to replace it when they throw you under the bus 45 days from now…

Is the 150 amp CB before or after the 200? If before then the #2/0 might be OK.

Good point, Robert…

Any more info or, better yet, pictures available, Mathew?

Robert & Larry,
Thank you. You get exactly what I was trying to ask. The 2/0 is definitely before the 200 amp breaker. The problem is that the wire after the breaker I cannot tell what size it is. It has a red strip along its side that I have seen before on 4/0 but the label is not visible and I don’t touch or move anything in the panels. In the original picture I attached the wire along the left of the picture is the downstream wire. I didn’t know if anyone could tell if those two look different from the 2/0 feeding the breaker. I’m sending another, but it’s more zoomed out so I doubt it will help. The left panel is 200 amps and the right 150. Please let me know. And if you’re not sure how would you proceed? I also doubt it would ever be an issue. The house is big but not huge. They probably just broke the need for 200 amps and needed two services. No well pump and only one oven and water heater. Two heat pumps is all. Look how light of a load the distribution panels are. Thank you.


Go to

That will give you access to the BestInspectors.Net Members shared folder on Go to the subfolder “BestInspectors.Net Free Software” and download “ResidentialElectricalService-20”.

That will take the guesswork out of any service size, service conductor size, or service conduit size questions.

I tried to enlarge your 1st photo to see more detail but it was blurry. It seems like there are a few problems here with the conductor size from the meter and the conductor size to the panels.

Where does the grounding electrode conductor terminate?