Why are metal gang boxes dangerous for temporary power applications?
- Metal boxes are designed for permanently wired installations, not portable temporary power.
- No weatherproofing except for outdoor-rated FS-type boxes.
- Risk of a "hot" box condition — a dangerous live-voltage fault on the metal enclosure (see details below).
- Hand hazard due to sharp metal edges.
• No weatherproofing except for outdoor location FS types.
• HOT box danger. (See below)
• Hand Hazard with sharp edges
What is a hot box, and how can a GFCI provide a false sense of security?
As the diagram shows, a metal gang box can develop a dangerous condition when the earth ground is poor or not connected. If a hot short occurs — meaning live voltage contacts the metal enclosure — the box itself becomes energized. This fault will not trip the circuit breaker. The GFCI will also fail to trip, because its sensor only monitors current imbalance on the load side of the receptacle, not a fault on the line side or enclosure. In this scenario, the GFCI offers no protection.
which the earth ground is poor or not connected. There can be a hot short to
the metal box in which you now have a “hot” box. The short will not trip the circuit
breaker nor will the GFCI trip. The GFCI sensor only watches the “load” side
of the receptacle, not the line side. The GFCI is worthless in this situation.
Solution:
Choose a non-metallic gang box from Ericson Manufacturing Co. These boxes are injection-molded from rubber, making them a significantly safer option than metal for drop cord, drop box, and cordset applications. Because the enclosure is non-conductive, a wiring fault cannot energize the box exterior — eliminating the hot box risk entirely.
Several options to chose from....click on a link below to learn more.
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