3 Wire Subpanel

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DBoone

DBoone

Senior Member
Location
Mississippi
Occupation
General Contractor
I'm helping a builder buddy of mine build a house for a couple and there is a meter/main on the exterior wall. It has a 200 amp breaker and has knockouts available for more breakers. Inside there is a 200 amp Eaton panel. The meter and interior panel are back to back and connected with pvc conduit.

When it was determined that the meter would have a main breaker I told my friend that the interior panel would now be a sub panel and need neutrals and equipment grounds separate, float the neutrals, bond the EGCs to the enclosure, run 4 wires between meter and interior panel.

Long story short, he ran his usual set-up. Service Entrance conductors between the two. No EGC. As he is making up the panel he asks me if he needs to connect the bonding strap. I told him that technically this is now a sub panel, needs 4 wires, etc....gave the whole spill again.

He's not running a 4th wire. Period.

So I told him under the circumstances, YES, connect the bonding strap because if you don't and someone adds a ground bar, those EGCs won't the bonded to the neutral and there will not be a path to trip the breaker, and if the panel enclosure became energized the strap will provide a path to trip the breaker.

Do you agree with my assessment?
 
If the job requires an inspection they will probably catch this and he will end up changing it anyway.

In my opinion he shouldn't use the bonding strap/screw, he should go back and do the job right from the start. Doesn't sound like it would be much trouble.

The neutral and ground will already be bonded at the meter/main.

All he needs to get in his head is that he is now wiring a sub panel. He needs a ground bar kit and keep his neutrals and ground seperate in the sub panel.
 
growler said:
If the job requires an inspection they will probably catch this and he will end up changing it anyway.

In my opinion he shouldn't use the bonding strap/screw, he should go back and do the job right from the start. Doesn't sound like it would be much trouble.

The neutral and ground will already be bonded at the meter/main.

All he needs to get in his head is that he is now wiring a sub panel. He needs a ground bar kit and keep his neutrals and ground seperate in the sub panel.
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:thumbsup:

I don't understand why pushing an EGC through the PVC is a problem.

Roger
 
roger said:
:thumbsup:

I don't understand why pushing an EGC through the PVC is a problem.

Roger
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I don't understand it either unless the guy is just hard headed.

Since the meter/main is already bonded there isn't a fix that wouldn't be a code violation.

Here if you are going to have to tear half the house apart to run SER/4 wire to an existing sub panel because a disconnect is required outside then you can use a meter socket and a seperate disconnect that is not pre-bonded and then bond at the panel.

The only thing I can think of is that maybe he already has his panel made up and doesn't want to go back and seperate the neutrals and grounds. Looking for an easy fix. There isn't one.

If the guy wants to read these comment he will see there is not an easy fix and the job must be redone to code. If there was another correct way to do things I'm sure some of us would know about it.
 
growler said:
Here if you are going to have to tear half the house apart to run SER/4 wire to an existing sub panel because a disconnect is required outside then you can use a meter socket and a seperate disconnect that is not pre-bonded and then bond at the panel.
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I once got a one time allowance/variance to do something similar to this, no amendment.

I was working for HVAC guy and after I wired an AHU and asked him what a service receptacle, his response was a blank look.

Inspector was cool and we came up with a solution.
 
No inspection on this house so it will stay as is.


I'm not sure why a 4th wire wasn't run. Maybe what Growler said, "hard-headed".
 
DBoone said:
No inspection on this house so it will stay as is.


I'm not sure why a 4th wire wasn't run. Maybe what Growler said, "hard-headed".
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Well then I am gonna say that your buddy is a bit of a fool.

The solution is too easy. What are we talking in time and money to fix this? Maybe an hour and 20 bucks?

I am not a hard case by any means, but I find this one hard to pass on.
 
DBoone said:
No inspection on this house so it will stay as is.
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The lack of an inspection shouldn't be the reason to let a violation go, it's the electrician (builder in this case) that is responsible.

Roger
 
And it isn't like not being up on more recent code changes (even though it has been ~ 10 years on the buildings supplied by feeders issue in this kind of situation) is the problem - on the same structure it has been the rule for a very long time that it will need separate grounded/grounding conductors.
 
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