Testing the wiring in an outdoor circuit

[studbike]

Forgive me if this is easy to search - I was not able to find anything obvious here or on YouTube. I've got an outdoor circuit that has failed. Specifically, one outlet failed and then the second one went about a year later, with no trip of the breaker. How do I test the wiring to make sure it hasn't been corroded etc? The obvious thing that comes to mind is to test the resistance using a multimeter and compare it to an indoor circuit of similar length but I don't have a one hundred foot long lead to span from edge of my yard to my panel... There must be an easier way, right? The other thought is just to get a voltage reading and again, compare it to a good outlet, but I'm not sure that's a sensitive enough test. I don't want to go digging up my yard willy nilly without evidence that the wiring is bad. Thanks for advice.

 

[aesmith]

I'm not an electrician.

With that qualification, and assuming you have this wiring completely isolated and confirmed dead. You could connect two of the conductors together at one end, then measure resistance between the two at the other end. Let's say it was 30m run, you then be measuring there and back, or 60m.

This will be only a really rough measure. If it's inconclusive then get an electrician with proper equipment to test it. As well as resistance, he'd probably also want to do an insulation test.

 

[Avo Mk8]

Just to follow up on the above, that is a good test for continuity, but really requires a meter specifically designed for low resistance, normally involving putting more current through the cable than a normal multimeter. Then based on knowing the cable size you have (some info is normally printed on it from which you can determine the cross sectional area and type of metal) so you can look up what the resistance ought to be and compare.

But there are other tests, such as insulation resistance, to check the cable is not leaking power to something.
This test is usually done with a meter designed for the purpose using a high voltage this time.
A common cause of problems with outside installations / underground cables is water ingress. If it's not obvious by checking at all the accessories for evidence of damp or corrosion, IR testing can help find the culprit.

Speaking from a UK pont of view, electricians here typically have the necessary test equipment and knowledge to fix the sort of problem you are describing. You can experiment with a multimeter, and look for the obvious in the switch boxes, outlets and accessories etc, but you may find the easiest way to resolve the problem is using an electrician with the right test equipment.

 

[Megawatt]

Forgive me if this is easy to search - I was not able to find anything obvious here or on YouTube. I've got an outdoor circuit that has failed. Specifically, one outlet failed and then the second one went about a year later, with no trip of the breaker. How do I test the wiring to make sure it hasn't been corroded etc? The obvious thing that comes to mind is to test the resistance using a multimeter and compare it to an indoor circuit of similar length but I don't have a one hundred foot long lead to span from edge of my yard to my panel... There must be an easier way, right? The other thought is just to get a voltage reading and again, compare it to a good outlet, but I'm not sure that's a sensitive enough test. I don't want to go digging up my yard willy nilly without evidence that the wiring is bad. Thanks for advice.

I honestly think that you need to troubleshoot the receptacles not working and is probably why you don’t have power outside.