I have 2 exterior outlets, controlled by 2 different interior switches. When I plug in my 3-prong outlet tester, the lights come on, albeit dimly, showing "power" and correct polarity. However, when I plug a light into the exterior outlet, there is not enough voltage to turn on the light bulb. (At least, that is what I think is happening.)

What can I troubleshoot next?

Thanks in advance!

 

For serious testing you need an analog (not digital) multimeter. A cheap $8-$15 one will be fine.

 

I have a Fluke 80 series III...is that digital?

 

It's digital but should work okay. First open up the receptacle and check the connections. If it is not a GFCI receptacle and is back stabbed move the wires to the screws. If it is a GFCI receptacle make sure the wire clamps are tight.

Make the following measurements:[list=1][*]Hot to neutral [*]Hot to ground[*]Neutral to ground[/list

Tell us your results.

Hot= Narrow slot
Neutral = Wide slot
Ground = half moon

 

Ray,

Hot to Neutral: 116V
Hot to GND: 124 V
Neutral to GND: 6V

Not a GFCI circuit...wiring was done circa 1966. Box is stucco'd in...so have not looked inside receptacle yet. Tried both a 3-prong "trouble light", and 2-prong polarized light...neither will turn on.

What do you think?

 

Neutral to ground should be 0v. You have an issue with that neutral wire. It sounds like it may not be connected either at that receptacle.... or wherever it comes from.

 

Ah, I will definitely check on that neutral wire, then. Guess I'm just going to have to cut that outlet box from the stucco. Thanks, PJ.

 

Only the cover plate needs to be removed. If the cover was stuccoed in that was a code violation. If the box is not flush with the surface of the stucco then you need to add an extension ring.

 

The cover plate is definitely stucco'd in. Same with the interior switch plates (adobe home...original switches from 1960's). Pretty sure we have a few more code violations, too. Argghh!

 

While you're opening this up, you'll also need to install a weather-resistant GFCI as well as an in-use cover.

 

I agree with a neutral issue, but I am going to guess you just have a poorly made neutral connection between where you tested it and the main service panel. That could account for the hot to neutral voltage being lower than the hot to ground voltage and would also account for you having a 6 volt reading neutral to ground.

 

The plot thickens....turns out both exterior outlets are controlled by the same interior switch! The second outlet (which is further from the switch than the first outlet mentioned below) has readings of:

Hot to Neutral: 115V
Hot to GND: 75 V
Neutral to GND: 6V

So, the 6V (Neutral-to-GND) is the same for both outlets. The Hot-to-GND is much lower for this second outlet (voltage drop?). There must be an underground Romex wire (I'm guessing underneath the sidewalk) between the 2 outlets, since the second outlet is embedded in a detached adobe courtyard wall. (The first outlet is attached to the exterior wall of our home.)

Have not pulled the covers yet, since I have to get brave and cut the stucco. Also, there are 9 interior switches that I am troubleshooting: a panel of 4 and a panel of 5. (That caused my confusion of thinking I had 2 interior switches controlling 2 exterior outlets in my original post!)

Thank you for all the great suggestions!! This is a very helpful forum!

 

Note: NM-b (AKA Romex) is not intended for use in wet locations such as buried conduit or direct burial. If you do have NM not UF that could be part of the problem.

 

Interesting...I did find some direct-buried Romex under another sidewalk...not associated with my outlet troubles listed on this thread. So, I would not be surprised if I do have an improperly buried cable somewhere.

I plan to remove the covers on both exterior outlets today.