Grounding and bonding

Words first

DC negative is the normal return conductor. Chassis bond connects a system point to vehicle metal. AC equipment ground is the safety conductor. Neutral is a current-carrying AC conductor. These jobs are related but not interchangeable.

AC bond behavior

Neutral and equipment ground are bonded at one correct source point, not everywhere. With shore power, that bond is normally upstream at the source. In inverter mode, some inverter-chargers create the bond internally and remove it during pass-through.

Metal van

Bond exposed metal enclosures and AC equipment as required. The chassis must never become an accidental current path through a damaged cable. Use an intentional, corrosion-resistant bonding point and protect penetrations.

Ground loops

Multiple unintended paths can carry current through signal shields, chassis or data grounds. Symptoms include noise, sensor errors and hot small wires. Draw every bond and follow one coherent architecture.

Non-negotiable

Follow the inverter/charger manufacturer's grounding and relay instructions exactly and have AC work reviewed by a qualified professional familiar with mobile/RV systems and local rules.

Rule of thumb

If you cannot state the expected current, full conductor length, protection rating and manufacturer limit for a circuit, the circuit is not ready to build.

CHAPTER CHECK

• I can explain the purpose of every component covered here. • I can identify the exact manufacturer limit that controls my design. • I have added the decision, rating or measurement to my schematic/worksheet.