Ask PYS: Power

John, on Feb 12, 2013 asked:

What is so special about marine grade duplex receptacles? Are they really necessary for interior spaces on a sailboat? Hubbell makes a yellow faced duplex receptacle, which I suspect it the same one marketed by Marinco and others. Typically they go for $38 to $45 EACH. A 'cheap' residential duplex receptacle goes for $1 and a commercial grade about $3. As near as I can tell most of the parts are identical and made with the same material as their 'commercial' grade duplex receptacle: nylon face, PET back, brass/nickel screws, galvanized steel backing plate (that surprised me), SS 'auto-ground' strap (not sure what that is) and the SAME certification. The other odd part is GFCIs. If you look those up in Hubbell's marine section they are the same as residential units. They claim these are okay by ABYC. If that's the case it actually makes sense to use them for every outlet (not necessary as the first one will protect the entire circuit), but at $20 each a lot cheaper than so-called 'marine grade' duplex receptacles. Keep up the great work and articles in PY!

You are right, the difference in price is astronomical. It's the first time I hear of marine grade AC receptacles, and therefore without actually looking at either side by side it's hard to say if the price difference is justified. Most boats and in our own installations we always use AC receptacles that have been tested and approved by inverter manufacturers. 

We always use GFCIs on the first outlet in the series of outlets. No need to have them on each outlet, as long as the first is protected. 

In closing, thanks for the kind words. It's much appreciated.