Tap Bus

[Alwayslearningelec]

See attached. What's bet way to accomplish this. Drill and tap would need engineer approval I'd think.
Anyway you could tap bus without drill/tap granted there's room?

 

[petersonra]

See attached. What's bet way to accomplish this. Drill and tap would need engineer approval I'd think.
Anyway you could tap bus without drill/tap granted there's room?

some manufacturers have kits to do this.

 

[augie47]

I hope someone takes AIC into account

 

[petersonra]

I hope someone takes AIC into account

Probably does not affect the tap itself.

 

[jim dungar]

Probably does not affect the tap itself.

You are correct that AIC is not an issue for the tap, however the SCA (available short circuit current) may definitely be a concern. It is common to see bus bracing and cable lacing required when the SCA approaches or exceeds 65kA.

 

[petersonra]

You are correct that AIC is not an issue for the tap, however the SCA (available short circuit current) may definitely be a concern. It is common to see bus bracing and cable lacing required when the SCA approaches or exceeds 65kA.

probably would be covered by the manufacturer's instructions for the tap kit.

 

[jim dungar]

probably would be covered by the manufacturer's instructions for the tap kit.

Maybe if a manufacturer's kit is used, but I have seen many custom lugs added in the field by the manufacturer that never considered this issue because it was not shown on the work order. You don't get what you don't ask for.

 

[Alwayslearningelec]

Maybe if a manufacturer's kit is used, but I have seen many custom lugs added in the field by the manufacturer that never considered this issue because it was not shown on the work order. You don't get what you don't ask for.

So if you add lugs to the bus to need to drill/tap to install them?

 

[Alwayslearningelec]

Can someone post a link to the kits your referring to. Thanks.

 

[petersonra]

Can someone post a link to the kits your referring to. Thanks.

you need to get them from the manufacturer of the switchboard

 

[Strathead]

So if you add lugs to the bus to need to drill/tap to install them?

It is more common for me to see holes drilled and nut and bolted not tapped and threaded.

 

[Alwayslearningelec]

It is more common for me to see holes drilled and nut and bolted not tapped and threaded.

What the difference between drilling holes and tapped/threaded? Thanks

 

[petersonra]

What the difference between drilling holes and tapped/threaded? Thanks

some people like to drill and tap the bus because they think it is a better connection. i think they are fooling themselves. the electrical connection is between the surfaces of the lug and the bus, not in the threads.

 

[jim dungar]

some people like to drill and tap the bus because they think it is a better connection. i think they are fooling themselves. the electrical connection is between the surfaces of the lug and the bus, not in the threads.

It is often hard to get proper thread strength for torqueing large bolts, so most copper bus connections are drilled with through holes.

 

[Alwayslearningelec]

some people like to drill and tap the bus because they think it is a better connection. i think they are fooling themselves. the electrical connection is between the surfaces of the lug and the bus, not in the threads.

Better connection than what? Guess what I’m asking is what other method is there to connect lugs to bus besides drill and tap? What’s the “tap” mean!? What do you do when you “tap”?

 

[electrofelon]

It is often hard to get proper thread strength for torqueing large bolts, so most copper bus connections are drilled with through holes.

If one were to tap, (not saying they should but if) they should use a forming tap instead of a cutting tap. They make stronger and higher quality thread.

 

[electrofelon]

Better connection than what? Guess what I’m asking is what other method is there to connect lugs to bus besides drill and tap? What’s the “tap” mean!? What do you do when you “tap”?

Out if curiosity is this a panelboard? I assume so by the size.

Well you've got to attach some new conductors to the buss somehow. Your options are:
1. Bolt on a new lug (new hole, existing holes, thru bolted, or threaded.
2. change an existing lug to one with more Ports
3. There are sometimes clamp kits that clamp onto the busbar.

My order of preference would be:

1. Use something approved or provided by the manufacturer
2. Change a lug
3. Add a lug to existing hole
4. Drill a new hole.
5. Say it can't be done and go to bar.

 

[Alwayslearningelec]

Out if curiosity is this a panelboard? I assume so by the size.

Well you've got to attach some new conductors to the buss somehow. Your options are:
1. Bolt on a new lug (new hole, existing holes, thru bolted, or threaded.
2. change an existing lug to one with more Ports
3. There are sometimes clamp kits that clamp onto the busbar.

My order of preference would be:

1. Use something approved or provided by the manufacturer
2. Change a lug
3. Add a lug to existing hole
4. Drill a new hole.
5. Say it can't be done and go to bar.

It’s a switchboard. Thank you. That was very clear. I actually spoke to my vendor who contacted Eaton and they said they don’t make a kit. Weird right?

 

[electrofelon]

It’s a switchboard. Thank you. That was very clear. I actually spoke to my vendor who contacted Eaton and they said they don’t make a kit. Weird right?

I have usually found that the bolted joints of busbars in switchboards conform to NEMA bolt patterns so if that the case you could bolt some lugs on there. Last time I did that I ran it by the inspector first and he said as long as I am not drilling and using listed lugs get would be ok with it. Obviously YMMV.

 

[jim dungar]

I actually spoke to my vendor who contacted Eaton and they said they don’t make a kit. Weird right?

No it is not weird at all.
I expect most manufacturers want you to get their field service group involved in any field modification to their equipment.