CODEX
550.10

Mobile and Manufactured Homes — Service and Feeder

Manufactured homes are fed by a specific feeder arrangement with the neutral and ground kept separate downstream of the service, unlike older bonded setups.

Introduced
1968
Level
NEC (National)
Why this code exists
Shock / electrocution
Current status
Active

Why this code exists

When a home is a separate structure fed from a service pedestal, bonding neutral to ground at the home would put current on metal parts people touch.

The service equipment sits at the pedestal, and the four-wire feeder to the home keeps the neutral and equipment ground as separate conductors. The neutral is only bonded back at the service, not at the home.

Older three-wire hookups bonded the two together at the home, and that is exactly the setup that energizes a metal skirt or a dryer frame when the neutral opens. Modern rules fixed that.

When it applies

This covers how manufactured and mobile homes get their power. These homes are fed by a feeder from a service located near the home, and a key point is that the neutral and the equipment ground stay separated inside the home, unlike an older setup where they might have been bonded together at the panel.

Common mistakes

In the field

The first thing I check on an older mobile home is whether the neutral and ground got separated at the panel. If they are still bonded, that is a shock hazard on the metal skin, and it is the fix I lead with.

Field note
I still find old three-wire hookups on manufactured homes where neutral and ground are tied together. I convert them to a proper four-wire feeder — a floating neutral on that setup can make the whole metal skirt hot.
— Priya · Journeyman · 12 yrs
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Codex is an independent educational reference. Not the National Electrical Code® and not affiliated with the NFPA. Always verify against the adopted code and your AHJ. · Privacy