Where should neutral and ground be bonded?
Only at the main disconnect. A subpanel with neutral and ground tied together is usually miswired. Get an electrician's bid before your deadline.
Updated · By 
Ben Sikes
Should neutral and ground be bonded in a subpanel?
Neutral and ground are bonded at one place only: the main service disconnect. Every panel after it in the same building keeps the two on separate bars. If your report says a subpanel has them tied together, have a licensed electrician open that panel and price the fix before your inspection deadline. Then ask the seller for the electrician's number, not a guess.
Key takeaways
- A visit runs $100 to $200 if it fits in the first hour and $250 to $590 with a four-hour minimum (HomeAdvisor), and more if the feeder needs a ground wire.
- A subpanel is typically fed by four wires: two hots, one neutral and one ground. Ask the electrician to check yours.
- Hand the electrician every electrical line on your report in one visit. It saves repeat service-call fees.
Why are neutral and ground bonded at the main panel?
Neutral and ground are bonded at the main panel through a part called the main bonding jumper. InterNACHI, the International Association of Certified Home Inspectors, says it provides "a low-impedance fault-current path back to the power supply to facilitate the tripping of the overcurrent device in case of a ground fault." In plain words, it lets a fault trip the breaker.
Leave that bond out and IAEI Magazine says the result can be "various issues, the least of which will be voltage fluctuations that may damage connected equipment." So the bond has to exist, and it has to exist once.
What does a bonded subpanel mean on my report?
A bonded subpanel means the neutral and ground are joined in a panel fed from the main one. InterNACHI says a subpanel keeps neutrals and grounds on separate bars, and only the ground bar is bonded to the metal box. It calls tying them together a common wiring mistake.
One exception: InterNACHI says that before 2008, a panel in a detached garage, barn or shop was sometimes wired with neutral and ground joined on purpose. If your panel is in a detached building, the electrician should confirm which case applies.
Your report may name one of these signs:
- The bonding screw, often green, is screwed down.
- The tie bar that joins the two bars is still in place.
- Neutral and ground wires share one bar.
Where the main disconnect sits matters. InterNACHI says that if the main breaker is outside at the meter base, the bond belongs there, not at the indoor panel. In that house, the indoor panel's neutral and ground bars must be separate.
Is a bonded subpanel dangerous?
IAEI Magazine says a second bond past the main service creates "parallel ground fault return paths that may not push the overcurrent device to react in a timely fashion." If the extra bond sits downstream of a ground-fault circuit interrupter (GFCI), the same article says "it will cause the device to trip."
Treat this as a safety finding. Have a licensed electrician open the subpanel before your deadline. They confirm whether the bars are tied, whether the feeder carries a separate ground wire, and what the fix involves at your house.
What does it cost to fix?
Until your written bid arrives, price the fix as electrician time. The table shows what that time costs.
| Source | What the figure covers | Cost |
|---|---|---|
| HomeAdvisor | First hour, billed as a service call | $100 to $200 |
| HomeAdvisor | Each hour after that | $50 to $130 per hour |
| Fixr | Typical service call, total | $176 to $327 |
| This Old House | Most small to medium electrical tasks, total | $150 to $600 |
Kept prices every line of an inspection report for $79, usually under 4 hours, and marks the ones that need a professional's quote.
Here is how HomeAdvisor's rows add up. If the fix fits in the first hour, you pay the service call alone. HomeAdvisor also says many electricians bill a minimum of one to four hours. With a four-hour minimum, the low end is $100 + (3 × $50) = $250 and the high end is $200 + (3 × $130) = $590.
None of these rows covers a new feeder. If your subpanel lacks a separate ground wire, the electrician's written bid is the only number to use.
Who fixes it, and can I get a number before my deadline?
A licensed electrician fixes it. HomeAdvisor says quotes for clearly defined fixes are often free, and bundling jobs into one visit cuts repeat service-call charges. So give the electrician your whole electrical list, and ask for the bid in writing.
If your report also lists an overfused breaker, add it to the same visit. The rest of the electrical list is covered in electrical findings on an inspection report. For getting bids fast, see how to get repair estimates during the inspection period.
What do I ask the seller for?
Ask for the electrician's bid total, and attach the bid. Ask for a credit if you want to pick the electrician, or the repair if you want it done before you own the house. If the seller does the work, ask for a licensed electrician and the paperwork before closing.
The line can be this short: "Subpanel neutral and ground bonded together. Licensed electrician to separate the bars, per the attached written bid."
The buyer repair request letter template has the wording. What to ask for after a home inspection covers where this line sits in the rest of your list.
What if the seller says no?
If the seller says no, start from the bid. Once an electrician prices it, this finding has a number. That makes it a line to negotiate, not by itself a reason to leave. It changes if the bid includes feeder work you did not budget for. Weigh that with when to walk away after a home inspection.
Your contract sets the exact deadline and terms, so confirm them with your agent.
Is a bonded subpanel a code violation?
Whether it is a code violation depends on the electrical code your city or county has adopted. IAEI Magazine's summary of National Electrical Code (NEC) section 250.24(A)(5) says that past the service main, "we are not to connect the grounded conductor" to any grounding conductors. The code has narrow exceptions, such as some existing dryer and range hookups. InterNACHI adds that before 2008, panels in detached garages, barns and shops were sometimes wired with neutrals and grounds joined, but never subpanels in the same structure. Your local building department or a licensed electrician says which rules apply to your panel.
How do I know what the rest of my list is worth?
If the subpanel is one finding among many, upload your inspection report to Kept and save your electrician's visit for the lines only they can price.
Sources
- InterNACHI, Inspecting the Main Electric Panelboard During a Home Inspection
- IAEI Magazine, Article 250: Grounding and Bonding
- IAEI Magazine, Current in the Grounded Conductor
- HomeAdvisor, How Much Does It Cost to Hire an Electrician?
- Fixr, Electrician Cost
- This Old House, How Much Does an Electrician Cost?
Cost figures are modeled from public wage and materials data unless a line says observed. Kept is accountable for the numbers on this page, and corrections go to support@usekept.com. How we price.