# Electrical main size

Observed this main today. It has (4) 150amp breakers tied to each othe as the main power off breaker. Havent seen one like this before. Is this considered a 600amp service?

I was taught that you never add

Ok if thats the case what does that make this?

What size is the conductor, what is the panel rated and what is the service meter rated?

That breaker is 150 amps.

I “think” it will end up being 150 amp, not knowing the answers above is critical though. I am open to learning if someone knows better though.

After having read some other posts and doing some investigation I think Jim your right. 150amp.

That’s the great thing about this board, is getting to talk to people and figure things out.

Well, I will try and help. It is a somewhat deceptive.

First, lets look at the cable terminations for the ungrounded conductors. Realizing that a 200 amp residential service requires 2/0 conductors, we can deduce that a 600 amp is going to require conductors on the magnitude 3 times larger. Looking at the photos, we can see single conductors terminating at single lugs. It is hard to tell just from looking at the photos, but those look at best to be 1/0 conductors.

Next, looking at the grounded or neutral conductor, we can also see that it would be insufficiently sized in the same proportion as the ungrounded conductors.

Finally, not shown in the photos, you could look at the service point and gain some more insight as to whether this would constitute a 600 amp service.

This is a 150 amp breaker.

This is a 150 amps service.

So do all 4 breakers need to be turned off to cut power? Do you have a picture of the whole panel without the cover? I am wondering how that works.

Technically that is one circuit breaker. You cannot operate those units individually since they’re all connected together with an internal trip mechanism. Look closely at the handle tie it says “common int trip”

I see the tie, but why 4 breakers?

It allows the manufacturer to use smaller cheaper units together to make one bigger breaker. Each individual unit in this case would be rated for 75 amps. the two on the top (75*2=150 amps @ 120 volts on one phase) the two on the bottom the same thing. Total=150 amps @ 240 volts.