Can a steel plate be used as a current carrying bus bar?

Status
Not open for further replies.
J

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
I looked at a new, in progress, 120/208V 3ph 4 wire 600 amp service for a friend he is having installed at his business. The 600 amp main disconnect (breaker) has its' own enclosure. Brand is Square D.

A steel plate, (bus bar?), is used for the Line parallel neutral conductors two barrel mechanical lug and the load neutral parallel conductors 2 barrel mechanical lug. The way the guy has it wired the steel plate is a current carrying conductor. Does a steel plate meet the definition of a current carrying bus bar? Is it code? If yes where would I find it in the 2017 NEC.

I've, seen, used, copper and aluminum bus bars. I've heard of brass bus bars but I never seen or used steel for a current carrying bus bar.

Notice in the picture the guy didn't even remove the paint from the steel plate where he installed the lugs. Or does Square D use conductive paint now days?

Picture of terminations.
.
 
J

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
@infinty,

Thanks.

200.2(B) is what I needed.

All the guy needed to do was stack, bolt, one mech lug on top the other and he would have met code.

I've got another thing I just started looking for in 250. The guy put 3" plastic bushings on the two 3" EMT/compression connectors, (nipples), that enter the main disconnect enclosure cabinet from the CT cabinet. Maybe it was an AHJ requirement but I remember having to use insulated throat grounding bushings on the service entrance conduits where they entered the service equipment and bond them to the grounded neutral conductor.

.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Jamesco said:
I've got another thing I just started looking for in 250. The guy put 3" plastic bushings on the two 3" EMT/compression connectors, (nipples), that enter the main disconnect enclosure cabinet from the CT cabinet. Maybe it was an AHJ requirement but I remember having to use insulated throat grounding bushings on the service entrance conduits where they entered the service equipment and bond them to the grounded neutral conductor.

.
Click to expand...
If you have EMT with service entrance conductors it is required to be bonded on one end with something other than standard locknuts. It can be a bonding locknut with plastic bushings.
 
J

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
infinity said:
If you have EMT with service entrance conductors it is required to be bonded on one end with something other than standard locknuts. It can be a bonding locknut with plastic bushings.
Click to expand...

They are not bonding lock nuts.

The conduits enter the enclosure above the breaker. Therein above live parts. The first electrical inspection for the service, the inspector told the electrician he had to change out the EMT connector lock nuts to sealing type lock nuts for a watertight connection. (Oops I forgot to mention the services is outdoors.) Doing a quick Google search I couldn't find combination sealing and ground bonding lock nuts. At any rate what the guy has now doesn't meet code. Another code violation.

.
 
electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
Jamesco said:
They are not bonding lock nuts.

The conduits enter the enclosure above the breaker. Therein above live parts. The first electrical inspection for the service, the inspector told the electrician he had to change out the EMT connector lock nuts to sealing type lock nuts for a watertight connection. (Oops I forgot to mention the services is outdoors.) Doing a quick Google search I couldn't find combination sealing and ground bonding lock nuts. At any rate what the guy has now doesn't meet code. Another code violation.

.
Click to expand...
Right, if those connectors enter above live parts they must be suitable for wet locations. But emt fittings used outside must be raintight. Did he not use RT fittings?

Sealing locknut's are technically only listed for rigid, not other fittings, but it's seems the inspector didn't know or care.

Split type bonding bushings are available, although if he has to replace those box connectors then he has to take it apart anyway.
 
J

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
electrofelon said:
Right, if those connectors enter above live parts they must be suitable for wet locations. But emt fittings used outside must be raintight. Did he not use RT fittings?

Sealing locknut's are technically only listed for rigid, not other fittings, but it's seems the inspector didn't know or care.
Click to expand...

I agree.

Here is a Link of what the connector looks like without the insulated throat though.
https://www.homedepot.com/p/Halex-3...t-Electrical-Metallic-Tube-EA-82330/203077012

I'm not sure why the inspector did not accept the connector rating as being water/rain tight. Maybe it was the raised ridge of the connector that is supposed to make a raintight seal against, around, the KO hole on the outside of the enclosure.

electrofelon said:
Sealing locknut's are technically only listed for rigid, not other fittings,
Click to expand...

Might be, but.... Maybe there was something about the EMT connector the inspector didn't like.

Maybe this.
The electrician installed two 2" nipples using the same type/manufacturer EMT connectors through the top part of the back of the outdoors raintight Square D panelboard above live parts. The electrician used the locknuts that came with the connectors. I had my friend pour water on/into the space between the panelboard and the building wall. Water came through area between the KO and the threaded throat of the connector. I verified, visually only, and the locknuts were made up mechanically tight. I will, have my friend, suggest to the electrical contractor he replace the locknuts with sealing locknuts.

.
 
Last edited:
J

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
infinity said:
If you have EMT with service entrance conductors it is required to be bonded on one end with something other than standard locknuts. It can be a bonding locknut with plastic bushings.
Click to expand...

250.92 (A) & (B)
That would apply to the CT cabinet as well. Correct?
 
T

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
If the the "electrician" that did this install does not understand basics like the rules for entering a 3R enclosure and the need for a listed neutral kit he should not be allowed to work unsupervised. The lack of competency in the trades today is appalling.
 
C

Carultch

Senior Member
Location
Massachusetts
Eddie702 said:
Related question (not to hijack the thread) but could you come in with EMT connectors with Myers Hubs?
Click to expand...

I've seen this done, and I don't entirely understand the point. If you are in a wet location, you have to use raintight conectors anyway, and raintight connectors can connect directly to the enclosure. What do you gain by adding the Myers hub?

Plus, Myers hubs are only listed to be used with RMC/IMC conduit, as is typical with most fittings that have female threads, tapered or straight. Any connector with straight male threads is meant to connect directly to the an enclosure wall, with its locknut as the female threadded component.
 
electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
Carultch said:
I've seen this done, and I don't entirely understand the point. If you are in a wet location, you have to use raintight conectors anyway, and raintight connectors can connect directly to the enclosure. What do you gain by adding the Myers hub?

Plus, Myers hubs are only listed to be used with RMC/IMC conduit, as is typical with most fittings that have female threads, tapered or straight. Any connector with straight male threads is meant to connect directly to the an enclosure wall, with its locknut as the female threadded component.
Click to expand...

I think some feel it is a higher quality install to use a Myers and connector and is preferable than using those hokey gaskets with the EMT connector. There seems to be two types of gaskets that come with RT fittings. One is rubber and those are absolutely atrocious as you can't tighten the locknut hardly at all before it deforms. Someone must have had a brother in law working for UL or payed a bribe to get those things listed. Absolutely disgusting that those things are approved. The other type has a hard plastic gasket which is better but still awful.
 
Status
Not open for further replies.
Top