• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Electrical service Q.

SCBO1

SCBO1

Platinum Member
Joined
Oct 28, 2009
Messages
4,352
Location
MID WEST
Can an electrical panel that was once used for a Sub-panel be re-used as a main house panel?

There was no main disconnect above the breakers and the sparky installed a 100-amp breaker on the side near the top on the right side of the breaker spaces. This 100-amp breaker receives the service entrance wires, so when you flip the 100-amp breaker, the panel should not be energized? He has all the other breakers neutrals on the the grounding lug and the old sub panel has an additional grounding bar added inside the panel. There is a ground rod and water-pipe ground on this set-up as well.

I have never seen this set-up before and can only find information on making a main panel into a sub-panel, not the other way around.

Is this a poor mans way, using an used panel?
 
IRC and IBC both have section 104.9.1 that says you cannot reuse used equipment unless approved by the building official. The NEC does not prohibit using used equipment if it is still sound. If the panel is in good shape, I would not refuse it on those grounds.

There is no real hazard to wiring a panel the way you describe, it is much less common, but I have no issues if the listing of the specific breaker or specific panel is not violated.
 
SCBO1 said:
Can an electrical panel that was once used for a Sub-panel be re-used as a main house panel?
This 100-amp breaker receives the service entrance wires, so when you flip the 100-amp breaker, the panel should not be energized?
Click to expand...
The busbar and the other breakers will not be energized, but service wires to the 100 amp breaker would be. If you are under the 2020 NEC or newer, you would have to find a way to guard those wires where they enter the 100 amp breaker in accordance with 230.62(B).
 
Does the label say "Suitable For Use As Service Equipment"? Where is the meter? Is there no other disconnect between the meter and the panel? Does the back-fed 100-amp breaker have hold-down hardware? Two ground rods are required.
 
Last edited:
This install looks like a sub-panel install with a grounding bar added in the panel. 100-amp breaker does not have any hold-down (SCREW) to keep the breaker from being easily removed . Grounding lug block is missing the green hold down screw and appears to be over torqued.
steveray said:
At a minimum...there has to be provisions for fastening the main breaker in place...Sparkies will chime in with better guidance...
Click to expand...
I think that is what is referred to as the hold down kit that is available.

Beniah Naylor said:
IRC and IBC both have section 104.9.1 that says you cannot reuse used equipment unless approved by the building official.
Click to expand...
The permit was taken out for a new service, contractor on the job indicated that the panel in the house was already there.

Exterior GEC is to the meter socket, so additional GE and GEC will need to be provided.

Water pipe GEC is ran to the additional grounding bar large lug.

To complicate this, the electric meter is still on and I can't follow the GEC to see if its a pass through the meter lug.

Thanks for listening.

TheCommish said:
Hire an licensed electrician.
Click to expand...
Ya, good idea
 
SCBO1 said:
This install looks like a sub-panel install with a grounding bar added in the panel. 100-amp breaker does not have any hold-down (SCREW) to keep the breaker from being easily removed . Grounding lug block is missing the green hold down screw and appears to be over torqued.

I think that is what is referred to as the hold down kit that is available.


The permit was taken out for a new service, contractor on the job indicated that the panel in the house was already there.

Exterior GEC is to the meter socket, so additional GE and GEC will need to be provided.

Water pipe GEC is ran to the additional grounding bar large lug.

To complicate this, the electric meter is still on and I can't follow the GEC to see if its a pass through the meter lug.

Thanks for listening.


Ya, good idea
Click to expand...
The GEC needs to connected to the utility GROUNDED conductor...it can be anywhere upstream of the main so the meter could work but the utility does not like that...
 
SCBO1 said:
Exterior GEC is to the meter socket, so additional GE and GEC will need to be provided.
Click to expand...
As far as the NEC is concerned, GECs and GE bonding jumpers can terminate at the neutral service conductor anywhere not downstream (not load side) of the service disconnect. So connecting to the neutral service conductor at a meter socket is perfectly fine, if the POCO allows it.

ICE nailed the potential issues:

- The panel needs to be rated and labeled "Suitable for Use as Service Equipment."
- The backfed main breaker needs a hold down kit.
- If the only electrodes are ground rod(s) and the water pipe, you need two ground rods (in practice; the alternative for one ground rod is generally harder than driving a 2nd ground rod) and you need to connect to the water pipe within 5' of its entrance into the building. Plus jumper around any possibly electrically impaired connections between the >= 10' underground portion of the metal water pipe and the GEC/bonding jumper connection to the water pipe, e.g. a water meter.
 
Where are two ground rods required? I see only one as a supplement to your water pipe:

2020 NEC 250.53(D)
(D) Metal Underground Water Pipe
If used as a grounding electrode, metal underground water pipe shall meet the requirements of 250.53(D)(1) and (D)(2).
(1) Continuity
Continuity of the grounding path or the bonding connection to interior piping shall not rely on water meters or filtering devices and similar equipment.
(2) Supplemental Electrode Required
A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(8). If the supplemental electrode is of the rod, pipe, or plate type, it shall comply with 250.53(A). The supplemental electrode shall be bonded to one of the following:
  1. Grounding electrode conductor
  2. Grounded service-entrance conductor
  3. Nonflexible grounded service raceway
  4. Any grounded service enclosure
  5. As provided by 250.32(B)
 
Beniah Naylor said:
Where are two ground rods required?
Click to expand...
Right here:

2020 NEC 250.53(D)(2) said:
. . . If the supplemental electrode is of the rod, pipe, or plate type, it shall comply with 250.53(A). . . .
Click to expand...

250.53(A) requires a single ground rod to itself be supplemented (unless you test at less than 25 ohms to remote earth, which is both unlikely and usually more trouble than driving a second ground rod), and the list of acceptable supplemental grounding electrodes excludes the water pipe electrode.

Cheers, Wayne
 
You must log in or register to reply here.
Top