Tapping and adding additional lugs to an existing service end box

[Tainted]

The building service is 208V 3-phase and has 10 sets coming into the building through the top of the service end box as shown in the pictures.

The service end box feeds 6 service switches, one service switch is 1200amps which feeds public lighting and power. You can see one of the 4 sets feeding the public lighting and power in the picture (first picture, 4 black wire on phase 3).

I want to upgrade the 1200amp service switch to a 4000amp service switch with a 3500amp fuse so that would require me an additional 6 lugs per phase.

I am trying to find where I can tap these 6 extra lugs, would it be possible to tap it on the existing bolts? There are 14 bolts on each side of the bus as shown. I'm not even sure if it's allowed since it's connecting and holding the other busses. Manufacturer of this equipment is unknown. Drilling busses is probably a nono.

 

[infinity]

Since you don't want to drill you could probably add a section of bus to accommodate your additional lugs using the existing holes. Might have to change out the bolts for longer ones.

 

[Tainted]

Since you don't want to drill you could probably add a section of bus to accommodate your additional lugs using the existing holes. Might have to change out the bolts for longer ones.

Good idea. but if an additional section of a bus is used, wouldn't that additional section of the bus require holes to mount it? Who should make the holes? are you allowed to get a separate thick copper plate and drill holes yourself? or must the copper bus manufacturer drill the holes?

I don't even know which jurisdiction I should ask if this would be allowed, is it utility and department of buildings or just utility?

 

[infinity]

Take out the short bolts and add the requisite number of layers of bus on top of the existing bus using the existing holes. The additional bus can overhang the existing bus with holes for your new lugs. You would likely need longer bolts. Best thing to do is to get a switchboard company out there and they should be able to fabricate anything that you need.

 

[Tainted]

Take out the short bolts and add the requisite number of layers of bus on top of the existing bus using the existing holes. The additional bus can overhang the existing bus with holes for your new lugs. You would likely need longer bolts. Best thing to do is to get a switchboard company out there and they should be able to fabricate anything that you need.

I like this idea, which manufacturer would you use? Preferably in NY. There aren't really many of them.

by the way, does this have to be UL approved if the service end box is being modified? UL enforcement has always been a gray area to me

 

[infinity]

There are several, All City Electric or Lincoln Electric are two of the bigger switchboard manufacturers in NYC (we recently used Lincoln for a 70 million dollar project). They should be able to tell if the modification falls within UL listing guidelines or if a NRTL needs to come out and field list the modification.

 

[Tainted]

There are several, All City Electric or Lincoln Electric are two of the bigger switchboard manufacturers in NYC (we recently used Lincoln for a 70 million dollar project). They should be able to tell if the modification falls within UL listing guidelines or if a NRTL needs to come out and field list the modification.

Got it, do these manufacturers require you to pay them before they go into the field visit? I never used any of them, don't even know how they work.

 

[augie47]

Could you put your lugs on the back side of the buss and use longer bolts ?? (mirror what you have)
All this assuming the buss has adequate ampacity.

 

[Tainted]

Could you put your lugs on the back side of the buss and use longer bolts ?? (mirror what you have)
All this assuming the buss has adequate ampacity.

Never though of that... something for me to look into, I like this idea too.

 

[Tainted]

Also what is the dimensions of the smallest 4000A service rated safety switch? Also need dimension of the 4000A CT. I gotta estimate where I can put it in the electrical room

 

[infinity]

Got it, do these manufacturers require you to pay them before they go into the field visit? I never used any of them, don't even know how they work.

I'm not sure but I would think that there may be an upfront cost refundable when you place the order.

 

[PCBelarge]

(I know, late to the show) There is only one proper way to attempt this type of installation. Call the manufacturer and have model number of the equipment. Ask him how to do this. I am willing to bet the farm they will not provide permission to drill the bus - it is all about the density of the existing bus. They will recommend a field rep to come out if they are even willing to do that. I would be surprised. I myself have made these calls for contractors that I consult for and have yet to receive a positive response.

 

[electrofelon]

I know this is an old thread, but since it was revived and no one mentioned it, how about just use stacking lugs?

Maybe the OP will give us an update

 

[PCBelarge]

Manufacturers design the bus to carry the listed amperage. As with other equipment, they do not usually over design. There are many manufactured bus bars with prepunched holes. Those are permitted to be used for additional terminations, but... Due to the listing, there is a limit to the amount of current/load to be added. Hence a phone call is a great idea, as they will follow up with a written response.