Today I asked for a quote on a 400A 2-gang meter socket with disconnects. What I got was a quote on a 400A 2-gang meter socket with (2) 200A breakers in each section. I was told that feeding a 400A MLO panel with (2) 200A paralleled breakers was OK. These breakers operate independent of each other and are factory installed in the meter socket section.
I have never come across this set-up before. According to 240.8 it seems to be OK. It just doesen't sound right to me.
Have any of you guys done this or seen this done before?
If I am understanding this set up, I would be worried about keeping the neutrals seperate between the services. Or if they are truly parallel I would think this would only have a 200 Amp capacity before tripping.
Sounds like 2 200a panels from that, not a single feed at 400a from it...... Unless they are linked in some way? Many class 320/400 resi services are like that.
From the commentary of 240.8
Section 240.8 prohibits the use of fuses or circuit breakers in parallel unless they are factory assembled in parallel and listed as a unit. Section 404.17 prohibits the use of fuses in parallel in fused switches. It is not the intent of 240.8 to restore the use of standard fuses in parallel in disconnect switches. However, 240.8 recognizes parallel low-voltage circuit breakers or fuses and parallel high-voltage circuit breakers or fuses if they are tested and factory assembled in parallel and listed as a unit.
Either way it sounds odd that a 400A 2-gang meter socket would have 4 200a CB's.... 800A of combined protection with no diversity on a 400A meter?
Got a model and make?
Mark Heller "Well - I oughta....." -Jackie Gleason
Ya, two 200A breakers are going to be around $1000 cheaper than one 400A breaker. Once you get past 200A, the price goes up pretty close to exponentially with ampacity.
If the documentation with the equipment says that it's intended for a 400A feed, then it's OK. But, I think the chances are upwards of 90% that this setup is intended to feed two 200A MLO panels, and isn't listed to feed a single 400A panel.
[This message has been edited by SolarPowered (edited 06-30-2006).]
You don't parallel breakers perod, or LV fuses that I am aware! You can discuss if in theory all that you want but it can not be applied. The only area where I have see fuses paralled is in medium voltage application where a specific fuse holders have been provided and ratings has been given for the combination.
Yesterday I called Tim Croushore of Allegheny Power. Tim is or was on a Code making panel (Don't know which one but his name is in the code book).
After I explained the situation he agreed that parallel breaker would not be compliant in this situation. He said that if the breakers were installed in the panel feeding a split buss it would be OK. That was not my case.
I told the supplier. The supplier wanted to get more info. He did say again that he has sold this set-up before and it was passed.
We'll see where this goes but we all learned something. I love it when that happens!