Casas móviles y prefabricadas — acometida y alimentador

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

• Bonding the neutral to the frame or ground inside the home's panel, which puts current on parts that should never carry it.
• Reusing a three-wire feeder from decades past instead of the four-wire arrangement now required.
• Undersizing the feeder for the home's connected load.

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.