Grounding vs bonding describes two different jobs that often get mixed up. Grounding connects an electrical system to the earth, while bonding connects metal parts together and to the neutral at a single point so a fault trips the breaker fast. The National Electrical Code covers both in Article 250, and placing the neutral-ground bond in the right spot matters in homes, RVs and inverter systems alike.
Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.
Grounding vs Bonding: The Short Version
- Grounding connects the electrical system to the earth, usually through ground rods or a water pipe. It limits voltage from lightning, utility surges and line contact. NEC Article 250 covers it.
- Bonding ties all metal enclosures, conduit and equipment grounding conductors together and to the neutral at one point. This creates a low-resistance path back to the source, so a fault draws high current and trips the breaker.
The earth itself is a poor conductor. It’s bonding, not the ground rod, that makes a breaker trip on a fault.
Where the Neutral-Ground Bond Belongs
In a typical US home, neutral and ground are bonded once, at the service equipment (usually the main panel). Subpanels keep neutral and ground on separate bars. A second bond lets normal neutral current flow on ground wires and metal parts.
RVs and Generators
- RV: the RV panel keeps neutral and ground separate. The bond is at the campground pedestal or the house service.
- Portable generator: many have a bonded neutral for standalone use. Connected through a transfer switch or inlet, it may need to be unbonded or switched, depending on whether the transfer switch switches the neutral. Follow the generator and transfer switch instructions.
Off-Grid and Inverter Systems
An inverter running on its own is a separately derived source and needs a neutral-ground bond to work safely. When it passes shore or grid power through, that bond has to open, because the source is already bonded. Inverter-chargers like the Victron MultiPlus do this with an internal ground relay.
| Situation | Bond location |
|---|---|
| House on grid | Main service panel only |
| Subpanel / detached building | Not bonded (separate bars) |
| RV on shore power | Pedestal or house service |
| Inverter on its own | At the inverter (often automatic) |
| Inverter passing grid through | Upstream; inverter bond opens |
Simplified. Local codes and equipment instructions govern.
Grounding vs Bonding at a Glance
| Grounding | Bonding | |
|---|---|---|
| Connects | System to earth (ground rods, water pipe) | Metal parts to each other and to neutral |
| Main purpose | Limits voltage from lightning, surges and line contact | Gives fault current a low-resistance path so the breaker trips |
| Where it happens | Grounding electrode system | At one point: the main service panel or the source |
| NEC article | 250, Part III | 250, Parts II and V |
Worked Example: Fault Current With and Without a Bond
Illustrative scenario: a 120V hot wire touches a metal appliance case on a 20A circuit.
| Path | Approx. resistance | Fault current (V ÷ R) | Result |
|---|---|---|---|
| Bonded equipment ground back to panel | 0.2Ω | about 600A | Breaker trips almost instantly |
| Earth only (ground rod, 25Ω) | 25Ω | about 4.8A | 20A breaker never trips; the case stays energized |
Resistances are illustrative; 25Ω is the NEC 250.53 benchmark for a single rod. This is why the earth alone can’t clear faults and bonding does the real protective work. The math is just the Ohm’s law formula.
Where the Bond Goes in Common Setups
| Setup | Neutral-ground bond location |
|---|---|
| House main panel | Main service disconnect only |
| House subpanel | None; neutral and ground bars kept separate |
| Portable generator powering an RV | Often bonded in the generator; check the manual |
| RV on shore power | At the park’s service, not in the RV |
| Inverter-charger | Many switch the bond automatically when inverting; check the manual |
| Off-grid cabin | At the main inverter or main panel, once |
Four-Step Bonding Check for a DIY System
- Identify the source of power: grid service, generator or inverter.
- Confirm exactly one neutral-ground bond downstream of that source.
- Confirm subpanels have separate neutral and ground bars.
- Bond the DC negative and equipment frames as the inverter manual and NEC 690 describe.
More background in neutral vs ground wire and GFCI vs AFCI.
Lightning and Surge
Grounding electrodes and surge protective devices help limit voltage spikes from lightning and utility switching. NEC 230.67 requires a surge protective device on new residential services under the 2020 code.
FAQ
Is grounding the same as bonding?
No. Grounding connects to earth. Bonding connects metal parts and the neutral so faults clear quickly.
Why does my GFCI trip on inverter power?
Often there’s a second neutral-ground bond, or no bond at all, somewhere in the system.
Should my subpanel have neutral and ground bonded?
No. In current US practice, only the service equipment is bonded.
Does a solar array need grounding?
Yes. NEC 690 Part V covers equipment grounding for PV modules and racking.
What is a ground rod for?
It connects the system to earth to limit surge voltages; it isn’t meant to clear faults on its own.
Sources: NFPA 70 (NEC) 2023, Article 250 and Article 210.8; OSHA, Electrical safety; NFPA 70 (NEC) Article 250 and 230.67. Accessed Oct 2026.
Related: Tadeto Circuit Breaker Finder Review, Proster Voltage Tester Pen Review