MLO panels

[cartman]

HELLO, could someone please tell me what the code rules are that apply to when you can use a MLO panel as opposed to a Main Breaker Panel. If you have a commercial building with a 6 gang meter pack outside that feeds 6 panels throughout the building can they all be MLO only or will a main breaker be required in each panel? Thank you for the info!

 

[russ]

Re: MLO panels

In this case you will Need Six mains, grouped together. 230.72
Plus see 230.70 for additional location info.

 

[russ]

Re: MLO panels

You could have one main with six feeders protected by the proper individual feeder overcurrent protection.

[ December 31, 2004, 05:30 PM: Message edited by: russ ]

 

[russ]

Re: MLO panels

I just realized my second post is goofy.

If these are different tenants, (like six different stores) you could have the individual mains in each store. I say you need a main, because I cant imagine a store with a panel with six or less circuits in it.

[ January 01, 2005, 05:14 AM: Message edited by: russ ]

 

[hurk27]

Re: MLO panels

This could get tricky as a firewall could render each store a seperate building and then each would have to have it's own main?

 

[midget]

Re: MLO panels

What's an MLO panel?

 

[peter d]

Re: MLO panels

Midget, you're like me, you ask a lot of questions.

Main Lug Only

 

[jtester]

Re: MLO panels

cartman
In general, you could use main lug panels in each of the 6 stores. You would need mains, service disconnects, grouped together at the meter stack. Look for MCB's where you need overcurrent protection or where you need a disconnect.
Hurk27 is correct, if the construction is such that the walls dividing each store are firewalls with certain specific ratings, each store could be a separate building or structure. Individual stores will almost always be separated by a firewall of some rating, but where I work, in a commercial building the firewall has to be a 3hr or 4hr wall before it is considered a separate building or structure and therefor would require a main breaker. Otherwise it is an area separation wall and does not create a separate building. This is up to the AHJ though.
Jim T

 

[midget]

Re: MLO panels

Originally posted by peter d:
Midget, you're like me, you ask a lot of questions.

Main Lug Only

LOL, well, for the most part I'm never really too sure yet where to look for information, so I just ask.

This time, though, I did some research...and now I have some more questions. So, a Main Lug Only Panel just has lugs for hots/neutrals...so there's no main breaker? Am I understanding this correctly? What kind of application would you use it in? Would you have to put a disconencting means for that panel? Fused or no?

 

[electricman2]

Re: MLO panels

So, a Main Lug Only Panel just has lugs for hots/neutrals...so there's no main breaker? Am I understanding this correctly?

Yes.

What kind of application would you use it in? Would you have to put a disconencting means for that panel? Fused or no?

For a sub-panel. It must be protected on its supply side by an OCPD rated no more than the panels current rating.

 

[cartman]

Re: MLO panels

So if I have a 100 amp disconnect outside of a building and feed a 100 amp panel inside the building it can be a MLO panel? thanks

 

[al hildenbrand]

Re: MLO panels

cartman,

Go back and reread what Russ, Wayne and Jim posted. Then take stock of the building(s) you are considering and find out from your local building officials that have jurisdiction over the building.