Hello all, first post here so go easy pls, this might be a dumb question. The question is: can I use a 480/277v 400A MLO panel (breakers as well) for a 208/120v 250A MLO service? I have one lying around and I'd like to save $$$. I'd like to know what determines the rating of a Main Lug panel if not the lugs themselves, and the feeders?? If that's the case then, the rating is a maximum and anything below it should be fine?? Please correct me if I'm wrong. I've been 14 years in the field, and I'm ashamed to not know the answer to this :ashamed1:.
Okay to use a 480/277v 400A MLO panel for a 208/120v 250A MLO service?
- Thread starter jd_u
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Yes, but a bit of a waste/overkill IMO.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
It's done all the time when high AIC ratings needs to be achived, very common install.
masterinbama
Senior Member
- Location
- Huntsville Alabama
Just be sure to label it properly with volts, phase etc.
Just because it's a 480v panel, you are not assured of a 22K rating. Some 480/277 breakers are 14K, some possibly lower.
Also, I assume there is some overciurrent device ahead of your MLO panel, correct ?
kwired
Electron manager
- Location
- NE Nebraska
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- EC
If this is the service panel as you appear to indicate, you are limited to only six breakers installed in the panel. If there is overcurrent protection ahead of it then it is not the service panel.
Do you have all the needed breakers already? Many times these type of panels are purchased with breakers at special pricing. Buying a panel with breakers costs less than buying the breakers alone in many cases. Serious, I one time had to add some circuits to an existing panel and ended up buying a panel and the breakers I needed plus some extra breakers for less than what they were going to charge me for just the needed breakers alone.
Do you have all the needed breakers already? Many times these type of panels are purchased with breakers at special pricing. Buying a panel with breakers costs less than buying the breakers alone in many cases. Serious, I one time had to add some circuits to an existing panel and ended up buying a panel and the breakers I needed plus some extra breakers for less than what they were going to charge me for just the needed breakers alone.
Yeah, these breakers are 25k @ 240v and below, and yes this is a sub off of a main which has the OCPD for this service.
No this panel is not the service. This panel will be the 3rd tier downstream from the service, and it's fed off a breaker. And yeah I know what you mean about the breaker pricing, especially since this is a Square D NQ. The only breakers that I need to add to this is a 3p 70a, and a 3P 40a, which might put me in the situation you just described... we'll see, thanks anyway.
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