Burnt receptacle Face plate

[alank]

Redeye50, if you had burn marks on the outside of the wall plate, I wouldn't worry too much about the receptacle, wouldn't hurt to look but I doubt you'll find any problem. In order to get burn marks on the outside the electrical arc had to occur on the outside. Check the plugs on the two heaters closely. Plug them in, turn on then pull and twist on the wire right at the plug and I think you'll find your problem. The wire connection to the plug prong is often deteriorated by the high current flow and is most likely where the arc came from to burn the outside of the plate.

[jsmmonaco]

JUST had the same problem with the receptacle for the engine block heater............my rv guy said it was due to a cheap out installed in the coach when manufactured........he swapped it out for a good one.....................

[REDEYE50]

Originally Posted by alank

Redeye50, if you had burn marks on the outside of the wall plate, I wouldn't worry too much about the receptacle, wouldn't hurt to look but I doubt you'll find any problem. In order to get burn marks on the outside the electrical arc had to occur on the outside. Check the plugs on the two heaters closely. Plug them in, turn on then pull and twist on the wire right at the plug and I think you'll find your problem. The wire connection to the plug prong is often deteriorated by the high current flow and is most likely where the arc came from to burn the outside of the plate.

Thanks, This makes since> I went ahead and changed the recepticle with a new one. I didn't find anything wrong besides burn;t marks. Iwill check the plug on the heater, looked at it once but will look again. Ofcourse I had to buy a regular MH recepticle for a$12.99 instead of a regular household one for $1.99. Oh well is a MH just like buying parts for a Corvette or a Harley! LOL

[Gary RVRoamer]

One thing that many are not aware of is that the amp rating on an outlet is for peak load, not sustained operation. Standard rating practice is to assume 80% load on average, with peak load limited to 30 minute periods. That means a 15A outlet can handle 12A for long periods but 15A only for 30 minutes or less. If you try to pull 13+ amps for 30+ minutes, chances are the outlet will gradually overheat and show signs of it, e.g. blackened pins, melted face plate, charring on the insulation. The cheaper grade outlets are likely to show symptoms earlier than the better ones. If any or the poor quality wiring conditions mentioned above are present, it may happen at even lower amp levels or shorter time.

This 80% rating rule is the primary reason that 120v electric space heaters have a max output of 1500 watts, which is about 80% of what a 15A outlet can provide in ideal conditions. UL & CSA won't certify them if they exceed the 80% load factor.

The same 80% rating rule applies to shore power outlets. That means a 30A shore hook-up is really good for only 24A sustained load. On a hot day with the a/c running non-stop, it's not unusual to get a sustained load in the 25-30A range, causing the outlet and attached shore plug or adapter to get quite hot.

[alank]

Originally Posted by Gary RVRoamer

The same 80% rating rule applies to shore power outlets. That means a 30A shore hook-up is really good for only 24A sustained load. On a hot day with the a/c running non-stop, it's not unusual to get a sustained load in the 25-30A range, causing the outlet and attached shore plug or adapter to get quite hot.

We were hooked up to a 30A post with our 50A coach at local campground and our 30A rubber plug had actually started to melt around the positive prong. Should have been watching it closer. At home I cut the plug up expecting to find a poor connection between the wire and the prong, but all looked good. I expect the positive connection in the receptacle was a bit corroded or lose which added to the heat generated at the plug. I've never had this happen before at a 30A post.