Refeeding 40A circuits

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Tainted

Tainted

Senior Member
Location
New York
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Engineer (PE)
a 100 unit apartment building has units that have 2-pole 40 amp breakers at 208V single phase. Only 1 meter feeds all the apartments and they want each apartment to be metered.

There are 2 panels that feed all the apartments. Each panel has 2-pole 40A breakers feeding them.

I would like to install the meter banks but the minimum breaker size for each meter is 60A so I can’t just refeed the 40A with a 60A breaker because i would need to upsize the entire 40A wires to accomodate the 60A breaker.

Is there any easy way to refeed the 40A apartments with 60A without upgrading the entire 40A wire?

I can’t just use a 60A wire on the line side of the 40A breaker because the panelboard won’t let me do that.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
put a set of 40 Amp fuses in the feeder wires. cost you maybe $50-75 per apartment for a set of class J fuses and fuseholders.

might be able to use the old panel boards as an enclosure for the new fuse blocks. would make it easier to connect up to the existing wires.

these would be taps from the 60 A breaker so if it met the tap rules you could run a wire with 40 A worth of ampacity to the fuse block.
 
Tainted

Tainted

Senior Member
Location
New York
Occupation
Engineer (PE)
petersonra said:
put a set of 40 Amp fuses in the feeder wires. cost you maybe $50-75 per apartment for a set of class J fuses and fuseholders.

might be able to use the old panel boards as an enclosure for the new fuse blocks. would make it easier to connect up to the existing wires.

these would be taps from the 60 A breaker so if it met the tap rules you could run a wire with 40 A worth of ampacity to the fuse block.
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If I modify the panel and install fuse holders in it, shouldn’t that modification be UL approved?
Are you allows to install fuse blocks in a long pullbox? I thought fuse block can only be installed in disconnect switches
 
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d0nut

Senior Member
Location
Omaha, NE
Tainted said:
I can’t just use a 60A wire on the line side of the 40A breaker because the panelboard won’t let me do that.
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Do the lugs not accommodate a #6, or is there some other reason why you are stating that you can't feed the panelboard with larger conductors?

Also, are you saying that each apartment has (2) 40A panels? If that is the case, I would look to combine to a single feeder to each apartment to simplify the metering.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Tainted said:
If I modify the panel and install fuse holders in it, shouldn’t that modification be UL approved?
Are you allows to install fuse blocks in a long pullbox? I thought fuse block can only be installed in disconnect switches
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The enclosure the panel board came in is just an enclosure. If you take the existing stuff out you can put whatever you want inside. Might need to have a new cover fabricated to screw on.
 
Tainted

Tainted

Senior Member
Location
New York
Occupation
Engineer (PE)
d0nut said:
Do the lugs not accommodate a #6, or is there some other reason why you are stating that you can't feed the panelboard with larger conductors?

Also, are you saying that each apartment has (2) 40A panels? If that is the case, I would look to combine to a single feeder to each apartment to simplify the metering.
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I am saying i can't refeed them using existing 40A circuit breakers because circuit breakers on that panel are not meant for line side wire connection.

I am saying there are 2 panels that feed the entire apartment units, maybe 50 units per panel.
 
Tainted

Tainted

Senior Member
Location
New York
Occupation
Engineer (PE)
petersonra said:
The enclosure the panel board came in is just an enclosure. If you take the existing stuff out you can put whatever you want inside. Might need to have a new cover fabricated to screw on.
Click to expand...
can i install a big pullbox and install the fuses there?
 
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curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Why is the minimum breaker for the meter stacks 60 amps? Most 125 amp socket meter stacks will accept 15 amp-125 amp 2-pole breakers.
 
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wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
From Eaton's Group Metering Catalog, see below.

If you are using a meter pack with plug-on tenant breakers, presumably you could use a BR240, BRH240, or BRHH240 in lieu of the 60 amp version, maybe confirm with Eaton. If you need BRX240, that doesn't seem to exist per the interwebs. For the bolt-on-type, I didn't investigate if 40A versions exist.

Cheers, Wayne

EatonTenantBreaker.jpg
 
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d0nut

Senior Member
Location
Omaha, NE
I might be a bit slow on the uptake as I am having some difficulty picturing what you are trying to do exactly. Maybe a sketch of a one-line or riser would help out?

If you are trying to individually meter each apartment from a meter stack, wouldn't you eliminate the two panels you have that currently feed the apartments and feed the apartments directly from the meter stack? The apartment panel lugs should be able to accommodate the larger conductors if you had to increase to 60A.
 
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d0nut

Senior Member
Location
Omaha, NE
wwhitney said:
I assume the goal is to avoid running new feeders to all 100 apartments.

Cheers, Wayne
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Agreed, but it may be easier than to try to find room to mount 100 fused disconnects, especially if you already need to find room for the meter stack for 100 apartments.
 
Tainted

Tainted

Senior Member
Location
New York
Occupation
Engineer (PE)
How do I mount the fuse blocks? is there a panel that will let me mount them? can I mount them in a large pull box?
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
electrofelon said:
Have you actually talked to an eating gear guy? Those are just regular plug on breakers seems like they could provide you with what you need regardless of what the catalog says
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You may also find it is not a catalog item to supply them with anything less than a 60 Amp breaker but you could still buy a lesser rated breaker and replace the 60 Amp breakers. If you could find 100 40 Amp breakers. If this turns out to work you would have 100 60 Amp breakers left to sell on ebay and could probably retire on the proceeds. :)
 
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