Questions: subpanel from a subpanel

[david5253]

Hi Everyone,

Long time lurker, first time poster. Really enjoy all the info available here. I have a subpanel in a detached garage fed from a 200 amp service in the house. See the attached pictures. It was inspected and approved with 3 wires and a ground attached to the garage footers. The neutral bar is bonded to the panel. Is this correct?

I am using MHF 2-2-2-4 wire to feed another subpanel in a detached building about 50 feet away. I will be using a 90 amp breaker to supply that. I have installed 2 ground rods at the new location. Question: Do I use a bonding screw on the new panel or separate the neutrals and the grounds in the load center? Also how would you recommend that I connect the 1 1/2" conduit to the load center in the garage. Do they make a box extender for a Homeline load center so I could go straight in from the side or how about a flexible conduit into top?

Thanks in advance for your help. I'm in Colorado and we're under the 2014 NEC

 

[zmaxmotorsports]

Hi Everyone,

Long time lurker, first time poster. Really enjoy all the info available here. I have a subpanel in a detached garage fed from a 200 amp service in the house. See the attached pictures. It was inspected and approved with 3 wires and a ground attached to the garage footers. The neutral bar is bonded to the panel. Is this correct?

I am using MHF 2-2-2-4 wire to feed another subpanel in a detached building about 50 feet away. I will be using a 90 amp breaker to supply that. I have installed 2 ground rods at the new location. Question: Do I use a bonding screw on the new panel or separate the neutrals and the grounds in the load center? Also how would you recommend that I connect the 1 1/2" conduit to the load center in the garage. Do they make a box extender for a Homeline load center so I could go straight in from the side or how about a flexible conduit into top?

Thanks in advance for your help. I'm in Colorado and we're under the 2014 NEC

That existing panel is a little rough looking by my standards,as long as it was inspected I guess.
Anyway Id either come out the bottom or top of the panel inside of wall depending on how youre going to access it outside.
As far as feeding the other panel I prefer to do things with copper in pipe myself,run 4 conductors and isolate your neutrals/grounds on new panel(no bonding screw)
I also prefer main breaker panels over subs without main,makes it easier to isolate things to work on them.
it also makes it easier to kill the power in case of an emergency,and it gets you past the 6 breaker rule.

 

[ryanjharvey]

If this is truly a sub-panel you have attached pictures of, the bonding screw should have been removed between neutral and ground as well as a separate equipment grounding conductor ran with (2) phase and (1) neutral [grounded] conductors unless your hard piped to you main panel with metal conduit which can serve as the equipment grounding conductor (although not common in residential applications)

Your grounded footer where your sub panel is would normally be considered a supplemental grounding electrode if it's located in an attached location to the house, but currently your only means of tying your service panel to the sub panel pictured is the neutral [grounded] conductor which is incorrect. A grounding electrode is not a substitution for an equipment grounding conductor.

Does you main panel (where your main breaker is and considered your service entrance) have a grounding electrode and electrode conductor to the grounding bus bar? Is your neutral [grounded] bar bonded to the grounding bar and panel chassis?

Sounds like you may have some other problems that need to be corrected first. The neutral [grounding] and grounded conductors should only be bonded at one place which is your service entrance panel.

Others let me know if I'm missing something.

Also, additional supplemental grounding electrodes are only required if your structure is detached ( although they don't hurt when they are installed properly)

 

[MTW]

That subpanel hookup doesn't meet the code if it was done recently, should of had the grounding conductor included in the feeder makeup.

Without the separate grounding conductor, DO NOT remove the existing bonding screw. Its your only source of equipment grounding without the conductor installed. Don't repeat this mistake on the new feeder.

For installing your underground. Cut the drywall below the panel carefully, there's wires in there. You already have an un-taped seam on one side no cutting required there. Cut the other side directly over the center of the stud on the right side. Use a straightedge to mark the center before cutting. Doing this carefully will allow you to reattach the drywall cutout back in the hole once wiring is complete.

For the underground. Bring the conduit down from the bottom of the of the loadcenter. Put a pullbox below the panel that is the same depth as the wall thickness 4 or 6". Come out of the back of the pullbox to head thru the wall. Once outside use an LB fitting to head down into the ground. Once the wire is pulled and connected, reattach the drywall you cut out earlier.

They don't make box extenders for loadcenters, you would normally surface mount the loadcenter for exposed conduit entries.

MTW Ω

 

[david5253]

If this is truly a sub-panel you have attached pictures of, the bonding screw should have been removed between neutral and ground as well as a separate equipment grounding conductor ran with (2) phase and (1) neutral [grounded] conductors unless your hard piped to you main panel with metal conduit which can serve as the equipment grounding conductor (although not common in residential applications)

Your grounded footer where your sub panel is would normally be considered a supplemental grounding electrode if it's located in an attached location to the house, but currently your only means of tying your service panel to the sub panel pictured is the neutral [grounded] conductor which is incorrect. A grounding electrode is not a substitution for an equipment grounding conductor.

Does you main panel (where your main breaker is and considered your service entrance) have a grounding electrode and electrode conductor to the grounding bus bar? Is your neutral [grounded] bar bonded to the grounding bar and panel chassis?

Sounds like you may have some other problems that need to be corrected first. The neutral [grounding] and grounded conductors should only be bonded at one place which is your service entrance panel.

Others let me know if I'm missing something.

Also, additional supplemental grounding electrodes are only required if your structure is detached ( although they don't hurt when they are installed properly)

Main breaker panel is bonded to the chassis, the garage is detached and has a ufer ground. This was installed in 2011 and inspected.

 

[ryanjharvey]

Main breaker panel is bonded to the chassis, the garage is detached and has a ufer ground. This was installed in 2011 and inspected.

Okay - the fact that a UFER ground or other grounding electrode was installed correctly doesn't correct the code violation that the inspector missed. Your still missing a separate equipment grounding conductor. You said it was inspected in 2011 but im not sure what version of the code was adopted where you are at that time.

As someone else stated, UNLESS you correct the equipment ground issue in the current install, the bonding screw needs to remain to keep the current flowing back to the main panel and transformer source.

You may have a different inspector this go around and this could cause you some problems if not corrected - may want to start that conversation early to see what they are going to make you do once you get back into this panel.

 

[theoldwizard1]

I have a subpanel in a detached garage fed from a 200 amp service in the house. See the attached pictures. It was inspected and approved with 3 wires and a ground attached to the garage footers. The neutral bar is bonded to the panel. Is this correct?

Main breaker panel is bonded to the chassis, the garage is detached and has a ufer ground. This was installed in 2011 and inspected.

It depends what code you were under when it was inspected. I would say if it was approved then you are fine.

 

[theoldwizard1]

Best answer is, check with the local building authority/inspectors.