Question: Recently I had a chance to check out the really neat electrical installation on a friend’s new boat. The photo shows the way the wiring is laid out behind the panel board. As an electrical contractor I can really appreciate the care it took to make this installation look so neat and orderly.

I do have a question though. The clear Lexan cover shown over the AC transfer switch (blue cylindrical part) seems kind of odd to me. As an electrical contractor I’m used to mounting equipment like this in a metal box to meet the electrical codes. Isn’t this also a requirement on boats?

AC Safety Cover

ABYC Standard E-11 requires high-voltage AC terminations to be inside an enclosure like this one made of Lexan.

Answer: Excellent question! What you see in the photo you sent in is truly representative of a first class job on a modern boat.

The Lexan cover is something that was debated quite extensively at the time the requirement to cover live AC (high-voltage) components and terminals on the back of a panel board was initiated. The truth is, there simply wasn’t and still isn’t any history of electrical arc faults on the back of boat electrical panels that contributed to electrical fires on board. The reason the covering is now a requirement under the ABYC E-11 Standard is to prevent the more likely problem of someone working on the electrical system accidentally coming into contact with live high-voltage electrical terminals and getting shocked. In fact, it is a requirement under the ABYC E-11 standard that all high-voltage AC terminations be made inside an enclosure that requires the use of hand tools to gain access.