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Kevin
Kevin, Licensed Electrical Contractor
Category: Electrical
Satisfied Customers: 3288
Experience:  30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License
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Need to ask a little later when I'm in the panel location.

Customer Question

Need to ask a little later when I'm in the panel location. I'll get back to you, thanks
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: Reading for a couple of hours sonI need some help in wiring a 100 amp sub panel with a main shutoff.
JA: How old is the system in question? And have you consulted an electrician yet?
Customer: New construction and noe consults yet.
JA: Do you plan on doing the work yourself?
Customer: Yes, all breakers are installed but I'm not clear on the main sub panel wiring.
JA: Anything else we should know to help you best?
Customer: Not yet but I will be back in touch. Ty
JA: OK. To minimize me, please click the down arrow at the top right corner of this box.
Customer: Finally have time to talk.
Submitted: 4 months ago.
Category: Electrical
Expert:  Kevin replied 4 months ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) What questions do you have on the sub-panel feeder circuit? How can I help?

2) Will the sub-panel be installed in a detached building?

Customer: replied 4 months ago.
Feeding a 100 amp sub panel with a shut off. In the sub panel, the two hits are tied into the hot lugs. Also the neitral(the bus bars are separated. The bare ground is in a separate bus bar Not tied to the panel. Some I am making a mistake some where. Can you help?
Customer: replied 4 months ago.
Not separate building. Sub panel is 25 feet from main 200 amp service panel.
Customer: replied 4 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Kevin replied 4 months ago.

Thanks for the replies.

1) A sub-panel feeder circuit requires 4 conductors......ie...... 2 hots, 1 neutral and 1 equipment grounding conductor.

2) On any sub-panel, the neutral must always be isolated from the panel metal enclosure. This means, DO NOT install the green main bonding screw or the main bonding jumper strap.

3) Yes, you are correct. On a sub-panel, the white neutrals will only land on the main neutral bus bar. You will require a separate equipment grounding bar to land any bare copper or green ground wires. DO NOT intermix neutrals and grounds onto the same bus bars, must be separate.

Customer: replied 4 months ago.
The neutral is in the neutral lug. Should the bare ground in separate bus bar be bonded to the panel?
Expert:  Kevin replied 4 months ago.

1) Yes, the ground wire needs to terminate to a separately installed equipment ground bar.

2) Neutral and ground are never bonded on a sub-panel. Therefore, don't install the green main bonding screw or a main bonding jumper strap on the neutral bus bar.

Customer: replied 4 months ago.
Done that. Still getting shorts on many circuits
Expert:  Kevin replied 4 months ago.

1) Are breakers tripping? Please provide more details?

Customer: replied 4 months ago.
No breakers are tripping. Testing plugs shows grounds to hot.
Expert:  Kevin replied 4 months ago.

If you want to discuss on the phone, then you will need to accept the phone offer service. Otherwise, we can continue chatting here. Either way works for me.

Hot to ground should always measure 120 volts. Same with hot to neutral.

Expert:  Kevin replied 4 months ago.

Reply back with any other questions and I will be more than happy to answer them for you.

Thanks............Kevin:)

Customer: replied 4 months ago.
dedicated circuits test fine. Others show a short. My first question is still "is the sub panel wired correctly?". Could I send you a picture?
Expert:  Kevin replied 4 months ago.

Yes, please send me a picture so I can review what you have in place.

1) You mentioned breakers are not tripping. A short circuit will always cause a breaker to trip. Not sure what you are referring to as a short circuit? Need more details please?

Customer: replied 4 months ago.
Will send in about an hour thank you.
Expert:  Kevin replied 4 months ago.

No problem, send it to me at your convenience.

Customer: replied 4 months ago.
Let me know if you received these, thanks
Expert:  Kevin replied 4 months ago.

Recv'd the 2 pics...Thanks.

1) Is this panel a main panel or a sub-panel?

Expert:  Kevin replied 4 months ago.

1) Is the panel a Square-D plug-on neutral panel?

Customer: replied 4 months ago.
100 amp sub pane.
Customer: replied 4 months ago.
Square D 100 amp panel with main shut off
Expert:  Kevin replied 4 months ago.

1) I am unable to determine from the pic. Is there a separate neutral bus bar located on the right side and a common neutral horizontal tie bar at the top that connected to the left side ground bar with the bare copper ground wires?

Customer: replied 4 months ago.
Two bus bars. One left and one right. Separated-the strap has been cut out on the right. Separate bus bar on bottom of panel for the no 5 bare ground.
Expert:  Kevin replied 4 months ago.

1) All of the ground wires need to terminate to a common equipment ground bar.

2) If the left and right bus bars are commonly tied via the top horizontal bar, the left and right are both acting as a neutral bus bar.

3) All of the bare ground wires need to terminate to a separate equipment ground bar.

4) Based on the pics', looks like the left and right bus bars are tied together from the horizontal bus bar?

Expert:  Kevin replied 4 months ago.

1) Many panelboards will have a common horizontal tie bar that is common to the left and right neutral bus bars. I suspect this is what you have in place, but I need confirmation.

2) A panelboard acting as a sub-panel is typically not furnished with a separate equipment ground bar as the equipment ground bar is usually purchased as a separate component.

Customer: replied 4 months ago.
No the bus bars are separated. The strap has been cut out on the right to separate them.
Expert:  Kevin replied 4 months ago.

1) Kill power to the main breaker and check for continuity between the left and right bus bars. They are tied together. Thus both appear to be acting as common neutral bus bars.

Customer: replied 4 months ago.
Ok will do tomorrow. I'll text in the morning.
Expert:  Kevin replied 4 months ago.

1) You can also confirm continuity from the neutral bus bar to the panel metal cabinet enclosure. There should be NO continuity.

Expert:  Kevin replied 4 months ago.

OK, very good. I will be logged on here tomorrow.

Thanks............Kevin:)

Customer: replied 4 months ago.
Ok
Expert:  Kevin replied 4 months ago.

Just come back to this same question and let me know what you find.

Take care for now and we'll catch up with you tomorrow...........Thanks...........Kevin:)

Customer: replied 4 months ago.
It's fixed. Had to bond neutral bus bar to panel. Have a great Holiday and thank you
Expert:  Kevin replied 4 months ago.

1) If the panel is configured as a sub-panel and there is a main means of disconnect upstream of the sub-panel, then the neutral bus bar does NOT get bonded to the panel metal enclosure.

The only time neutral and ground are bonded together is at the main service disconnect and NEVER at a downstream sub-panel.

Bonding neutral to ground at a sub-panel is a code violation.

Hope this helps………If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks..................Kevin:)

Expert:  Kevin replied 4 months ago.

1) The location (main disconnect switch or a main breaker) where the main power can be killed to the home is the only location where neutral and ground are bonded. A sub-panel is NOT the main means of disconnect as there should be a disco switch or a main breaker upstream of the sub-panel.

Expert:  Kevin replied 3 months ago.

Just wanted to follow-up with you and see if you have any other questions that I can answer?

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