I have an outside shed that runs off its own designated breaker from my house. I have power to all outlets and switches. If I plug in a load or turn on the lights I lose all power without tripping the breaker. There are no gfi on the circuit. I replaced all the receptacles and light switches and inspected the wires in the process. Something is killing the power when I apply a load. Thanks for any help.

 

Sure sounds like a broken wire or loose/bad connection. First thing I'd check is that the connection to the breaker is tight and also the corresponding neutral connection.

If you have a meter, I'd monitor the voltage first at the breaker and then where the feed first comes into the shed while you turn the lights on and off. If the voltage is dropping in the shed but not at the breaker, you have a break in the feed. Remember problem could be in the hot or neutral. If you have any backstabbed outlets (where the wires go in the little holes and are not attached to the screws, that would be a suspect too.

 

I will add to Carbide's suggestion that you also check the integrity of the connection between the breaker and the bus stab. This is the kind of failure you might see with a bad panel design like Zinsco.

 

A bad connection with the bus stab will show a voltage loss at the breaker screw (and also everywhere downstream) when something is turned on (load is applied).

Direct bury cable can be attacked by animals and then the wires, especially if aluminum, can corrode.

 

If direct burial cable what kind was used?

 

You guys have forgotten to ask the first question of woodpile; what kind of device is he/she using to determine that there is "power" to the shed? If it is a non-contact type of tester then woodpile needs to use a real meter, light or solenoid tester BEFORE stating that "power" is available.

Even if the "hot" lead is energized it could be a failure of the "neutral" conductor.

 

Thanks for your input, I think the breaker should be my next step. I used a multimeter and checked where the wire comes out of the ground it read 110. When I went to the box in the shed where it emerges from underground I got no voltage. I then took off the two wires attached to the power coming in (feeding the shed) and I had 110 volts. I then attached one set of the wires back to see if had power to the outlets and I didn't. It took me awhile to figure out since I had to go to my house and turn power off, because I used the outside light as my indicator that I had power. Then I replaced all outlets and switches (original since 1969) assuming I had a bad one that was causing problem. I turned the power back on from breaker still using my outside light as an indicator and nothing. back to bldg. now and used a light volt indicator and tested the outlets and light switches and had no power,...I turned the light switch off, and tested and had power. checked all outlets and had power. plugged in a work light didn't work. Used the indicator and had no power at any outlets. Unplugged the work light and now get power readings at all recpt. and switches, but soon as I apply a load, kills every thing. All the while nothing trips the breaker. Sorry for the long post and thanks to all. I'll look at my breaker over weekend and let you all know if that fixes me up.

I'm not sure what wire is underground #10 at least and not aluminum. I have no backstabbed all screwd.

 

Well I changed the breaker today and more of the same. The power cable from my house goes to a shed that was lost to a tree many fears ago. There is a junction box and a cable underground to the problem shed. I attached a new cable (temp) above ground from old shed junction to problem shed and power is restored with no problems. My lack of understanding caused me many wasted hours. My thanks to all for your insight.

 

Find where the power comes into the shed and disconnect it from the shed wiring.
Connect a receptacle to the wires (use a pig tail if needed and wire nuts) and connect your load and see if it works. If it does, then the issue is in the shed.

If it does not work, then find where the wiring leaves the house. Disconnect the wires going to the shed and do the same test. If it works, your issue is in the buried wires.