Are independent EGC required for multi motor circuits sharing the same conduit?

[Dyegunny357]

If I have 3 different 3 phase motor circuits using thhn from a MCC in the same raceway. does the nec require 3 independent EGC one for each motor circuit?

At my work I commonly find that guys say the Code requires each motor to have an independent egc even if in the same raceway.

All I can find in the nec for multiple circuits in a raceway is article 250.122 C. No where in art 430 can I find that this is a requirement.

Can any shed some light is the just a field preference?

 

[ptonsparky]

No, they do not require independent EGs. The common EG should be sized for the largest required. # 12 to smaller motors could be tapped from a #4 that is required for the largest.

Or use the metallic raceway.

 

[infinity]

If I have 3 different 3 phase motor circuits using thhn from a MCC in the same raceway. does the nec require 3 independent EGC one for each motor circuit?

More than one properly sized EGC for all three loads is a waste of money.

 

[kwired]

Only place I have done such a thing (and wasn't necessarily limited to motors) was if you maybe had some T conduit bodies to branch off the raceway to individual loads, but did not want to or have the needed space in the T to splice the EGC's. Also usually was somewhat short run of the conductors making it easy/simple to just run separate EGC's vs coming spending $$ on some method to make room for the splices.

 

[Dyegunny357]

Only place I have done such a thing (and wasn't necessarily limited to motors) was if you maybe had some T conduit bodies to branch off the raceway to individual loads, but did not want to or have the needed space in the T to splice the EGC's. Also usually was somewhat short run of the conductors making it easy/simple to just run separate EGC's vs coming spending $$ on some method to make room for the splices.

I completely understand what your saying if there was tee fittings not wanting to splice inside even tho the code does allow us to splice especially since most fittings have a cu in marking now. Never would I use them to splice current carrying but EGCs I have no issue with.

I just thought I’d ask for different opinion from other electricians since maybe I was missing something in the NEC. Or even using the incorrect article when stating that 250.122 C allows us to use one egc sized to the largest overcurrent / short circuit device in raceway per table 250.122.

 

[tom baker]

Keep in mind there may of job or company specifications, or perhaps it was a this is how’s it’s done, passed down from previous generations.

 

[petersonra]

Not a code requirement.

 

[Dyegunny357]

Keep in mind there may of job or company specifications, or perhaps it was a this is how’s it’s done, passed down from previous generations.

I completely understand that principle but that doesn’t mean it’s code it means it a personal preference. We are to install per nec or greater than since nec is minimum.

Just cause it’s been done that way doesn’t always mean it’s correct or the most cost effective way to install especially with cost of copper wiring in today’s market. If you have to price for this extra cost in the competitive biding market it’s lost jobs due to wasteful unnecessary spending for the customer.

We don’t run ten current carrying #12s from one breaker just cause we don’t want to splice in a box to get to other devices or that’s just the way we always done it. That’s lost revenue to business

 

[kwired]

I completely understand what your saying if there was tee fittings not wanting to splice inside even tho the code does allow us to splice especially since most fittings have a cu in marking now. Never would I use them to splice current carrying but EGCs I have no issue with.

I just thought I’d ask for different opinion from other electricians since maybe I was missing something in the NEC. Or even using the incorrect article when stating that 250.122 C allows us to use one egc sized to the largest overcurrent / short circuit device in raceway per table 250.122.

I have used oversized conduit bodies to gain volume needed for splicing before. Whether it just be enough to splice the EGC or enough to splice more than that. Usually you don't want to splice any more than what is branching off at the tee though that can use up your fill allowance pretty fast.