Pool pump receptacle, burning.

[Npstewart]

Someone that works in my office has an above ground pool. He is plugging the pool pump in with a extension cord. The pump is 115V, 1 horse power. He is saying that the outside of the receptacle, which is a quadplex, is turning brown. The quad is located outside under a roof with no cover.

According to the NEC the pump pulls about 8 amps, and the quad is on its own circuit so I dont think its being overloaded. Anyone know why the receptacle is turning brown (ie burning) on the outside? Perhaps water is in there? He says its after its left on for a while.

 

[charlie b]

My best guess is corrosion internal to the receptacle. A loose wire is another possibility. Presuming the extension cord is not too long, and that only the receptacle (not the other end of the extension cord) is getting hot, and given that the problem only arises when the receptacle is in use, everything points to the internals of the receptacle itself. I recommend that your co-worker have an electrician take a look at it. It probably should be replaced with a receptacle that is protected by GFCI and that is rated for its outdoor location.

 

[RICK NAPIER]

Unless it is a storable pool it should not be on an extension cord. What is the wire size of the extension cord and what is the distance it travels?

 

[Npstewart]

Thanks for your help, everything makes sense with the corrosion

Nick

 

[Npstewart]

He said the extension cord is less then 15' so I didnt think voltage drop would be a problem. Ill ask him what size cord he is using.

 

[kingpb]

Don't quads contain either 2 x 15A or 2 x 20A rated duplex receptacles in a single box?

If that is what you are referring too, then they are going to be rated 15A or 20A, the breaker is probably 20A, which is OK.

A 115V, 1Hp motor is drawing 16A (Table 430.248) not sure how the 8A was determined.

The starting current is going to be close to 100A, and that 100A will be generated eveytrime the motor is turned on or off.

I'd say there's a chance that the continuous power is too much for the device, and for sure the starting current will take it's toll. Being outside the additional heating effect of the sun could be added to the stress of the device.

My recommenation would be to put it on a dedicated circuit, designed specifcally for the application.

 

[LarryFine]

I bet the extension cord's plug is hot, from the internal crimps.

 

[LJSMITH1]

I concur with others..Voltage drop on the extension cord, plus possible contact resistance problems caused by corrosion or heat. Either way, heat is discoloring the plastic, and also causing the contacts to loose spring pressure, which then increases contact resistance...

Many general use extension cords are 18 ga or 16 ga conductors. You would really need a 14 ga or 12 ga cord for that 1hp motor to eliminate any voltage drop issues - especially on startup.

If there is no inline or motor mounted switch/control, perhaps the HO is turning the pump on and off just by plugging in and unplugging the cord. If so, you will wear out the receptacle contacts fairly quickly.

The receptacle should also have an in-use cover on it to protect the devices from the weather.

 

[Npstewart]

I just spoke with him again. I guess I mis-understood him, he said that the extension cord is over 50' long!!! I told him to get a multimeter and measure the voltage on the other end of the extension cord.

I know this is by far not a legal installation but whether I help him or not, its going to be done illegally anyway.

Ill tell him the voltage has to be at least 108 volts because the motor is listed for 115 volts.

 

[LarryFine]

I told him to get a multimeter and measure the voltage on the other end of the extension cord.

" . . . with the motor running."

 

[dmagyar]

Doesn't sound very wise of you

Doesn't sound very wise of you

I know this is by far not a legal installation but whether I help him or not, its going to be done illegally anyway.

First of all you seem to be already accepting that you're going to get involved and help someone with a repair/rework that won't be legal? I remember my dad doing someone in the neighborhood a favor and installed a dryer plug for them with a good installation. From then on, any and everything that happened that was supplied from the homeowners panel was my dads fault.

"Before "Joe" did the work, we never had any electrical problems, what did he do wrong?" What I learned from that was to becarefull what you get yourself into.

No matter which way the homeowner repairs this, if you get involved even to the point of advice you'll be remembered long after they've forgotten that you did it for little or nothing. What they'll remember is that when the cord shorted out and someone got hurt, you were involved.