Power problem indicated by "weak" microwave?

[davida]

When I bought the 79 sovereign, it came with a newish microwave. The trailer is now installed at its permanent location, but hooked through an extension cord to a neighbor's GFPC outlet until I build a power shed.

When I tried the microwave, it would start "sounding" ok and then sound as if it was straining after about 1/2sec. I assumed the microwave was failing, so got a second microwave. This microwave does the same thing. Occam suggests that the problem isn't in the microwave but in the power supply.

I need to lug the microwave to the neighbor's and try it directly there, but I'd be very surprised if it didn't work just fine over there (he's got a simple electrical setup connected to the grid.

Is it possible that something about the power setup in the trailer is causing the problem? Some sort of maximum draw problem? The highest wattage thing we plug in (not at the same time as the microwave) is a space heater, but it's hard to know if it's operating at 100% power or not. Its fan isn't slowing down after 1/2 second.

Any pointers appreciated!

[ROBERTSUNRUS]

Hi, if you are useing a long skinny extension cord, that would most likely be your problem. The longer the cord, the larger diameter cord you need. Even with a large cord distance is your power killer.

[lewster]

Davida,

How long is the distance from the trailer to the outlet you are using? What is the rating on that outlet and it's circuit breaker in the box?

Depending on the length of the extension cord, you are probably experiencing 'voltage drop' that is caused by the internal resistance found in the wire. You should be using a MINIMUM of 12 AWG wire for your extension cord. If you are over 50', I would go to 10 AWG wire until you can get your permanent wiring in place.

That should stop the voltage drop and let the micro run. You can damage a motor severely by running it on sub-standard voltage!

BTW, I wouldn't run your A/C and the micro at the same time on a 20 amp circuit.......it will overload.

[davida]

I learned all about that when studying power lines, but never realized it'd come in handy in Real Life(tm).

Yet another reason to get my act together for the shed.

Thanks again!

[SLVRSRFR]

Depending on your appliances and power consumption you may have to account for power factors when using long distance hook ups.(The distance may cause a surge with inductive loads even though there is no over load) Please be sure to note that no matter what size/type Circuit Breaker and Receptacle you are using to check the amperage capacity on the wire for your feed. Especially on "custom jobs". Also, ampacities differ between types of wire. Dont mean at all to rain on any ones parade; I have just seen a lot of dangerous fire hazards in my trade as an electrician. Happy Travels!