Outdoor light post help

My outdoor light post recently stopped working. New bulb didn't fix it, no tripped breaker, indoor switch is good, and checked/reset all of the known GFCIs.

My source wiring includes a black, white, red, and green wire. The original connection to the fixture was the black (hot) + white (neutral) and the red wire was capped off.

My multi-meter test results are as follows with the switch in the ON position:

black (hot) + white (neutral) = 0 to maybe 2V
black (hot) + green (ground) = 100-115V
white (neutral) + green (ground) = 100-115V
red (2nd hot?) + white (neutral) = 100-115V

Tried connecting the red + white to the fixture but no luck.

No recent landscaping work, etc was done so I don't suspect a severed wire.

Scoured the internet for suggestions but all recommended tests were exhausted and failed, and I get the standard "time to call an electrician".

Any ideas or suggested additional tests?

Thanks in advance for your help!

 

Welcome to the forums.

Your problem there by the voltages you posted is an open neutral.

Do you have four individual wires there with the ground being green ?
That would signify wiring in a conduit.

One end would be at the light post....you'd need to locate the other end of the conduit.
Possibly in the basement ?

Are there any outdoor boxes or receptacles involved with this circuit ?

 

Thanks Pete, indeed based on additional research, and your diagnosis, it seems I have an open neutral.

The green ground wire originates from a clamp which is clamped around the conduit and which was then connected to the light fixture in the original setup. Inside the conduit are the black, neutral, and red wires. As additional detail, this light post is on top of a 2' x 2' x 4' brick base located at driveway entry.

I do have 2-3 additional outdoor floating receptacles between the light post and the house which are intended for 120V landscape lighting. However none of these receptacles ever worked since I purchased the house a year ago.

I later today checked one of these extra receptacles and observed the following:

-it has a GFCI but seems to be jammed, i.e. both reset and test buttons are stuck and can't be pressed
-the outlet box / conduit gets very hot to the touch when switched on
-this receptacle seems to work on the same switch as the light post based on the aforementioned "heating" issue - so I guess logically they must be on the same circuit
-this outlet is not functioning as mentioned but I have not done a comprehensive multi-meter test on it yet as I did on the light post. I will do so and report back.

Pleased to hear suggested next steps, thanks for the guidance which is much appreciated!

Maurice

 

I'm thinking your GFI receptacle is waterlogged and is heating up.
The next step would probably be to disconnect it.

If you had a short.... the breaker would trip.

 

Thanks Pete, there are two wires entering that outlet, one blue and one white. Those have been disconnected and capped off.

I checked the other exterior outlet and found it to be completely burnt/charred. I removed the outlet, separated the wires, and capped them off. That box had 3 wires though, a white wire, brownish wire, and blue wire. I suppose replacing that box with a new outlet should do the trick?

 

As you work on these problems we need to find the wiring that goes to the post light.
I can't see what you have there.... are these receptacles part of the same circuit and fed thru the same conduit as the light.

The brownish wire sounds like it might actually be red.

 

Open up all of the receptacle boxes as well as the switch inside (or if the conduit transitions to cable at some point before the switch) and post clear pics of what you have.

Are the other outlets arranged in an obvious line from the post to the house? The presence of the capped red in the post seems like there should be two separate circuits involved, one for the light itself that carries through all the boxes, then another for outlets that should have been constant - with the red carried through to the post for an outlet on it.

 

Hi Pete, I suspect they are part of the same circuit. I have 3 exterior electrical points in the front yard being the 2 receptacles and the light post. The one receptacle (non burnt) as mentioned heats up only when the light post switch is turned on - so that one for sure seems to be on the same circuit. The other though I can't say for sure but seems like it would be since it is located just about 12 ft from the other receptacle.

The only unclear thing is why one receptacle has three wires and the other only two (i.e. missing the red)...

I suppose I can check for continuity on the neutral wire between the light post and these receptacles by rigging up an extension cord. Is that the right next step?

 

The red wire would usually signify a switched source.
Were the receptacle and light both switched together ?

 

I directly reconnected the two neutral wires in the burnt outlet box and that seemed to do the trick...light post on! Thanks for the help & guidance! My outlet boxes are old and not properly insulated so I'll take the opportunity to replace both with new/better equipment.

My only continued concern is the high heat of the conduit on the second outlet box (not the burnt one). It's untouchably hot within 30 seconds once the switch is turned on.

There's a ground clamp attached to the conduit by the light post but otherwise nothing else stands out in my mind. The outlet box that burnt doesn't heat up like this one but maybe that's what burnt it in the first place...? That receptacle was fully melted.

Any ideas?

 

Sounds like an open neutral and the conduit is carrying current.

 

It takes a lot of current flow to melt a receptacle.
I would also be very concerned about a warm/hot conduit.

It would take an awfully big post light to draw enough current to make the conduit warm even if the conduit is being used to carry the neutral.


The circuit should logically be set up with three wires coming from the house. Red-switched power, black-always live and white-neutral. There may also be a separate ground.

I would expect to find 2 reds, 2 blacks, and 2 whites at each receptacle box. You mentioned only two wires at one box and three at another. That leads me to believe there may be a splice box in line where the wiring is interconnected.

 

Ok, so any ideas as to what specifically could be causing the heating? Could it be a bare wire making contact within the conduit somewhere along the line?

See below some pics just for reference (and sorry I could not get the pictures to rotate correctly)

Below is the box (box 1) which has only 2 wires and is the one that heats up



Below is the second set (box 2 and box 2a). The box towards the top of the image (box 2) is where the burnt outlet was located. The box below that one (box 2a) houses the wires that feed into the back of box 2.



Below is the wiring in box 2



Below is the wiring in box 2a. Note in this image, there is a blue and white wire going down the conduit on the right which I suspect leads to box 1. You can also see the white wire, which is barely noticeable in the conduit, appears severed.



And finally, below is the light post wiring

 

The wiring is not interconnected. There is a red wire at your post light that is not in those receptacle boxes. There is a location you are missing.

On the box that gets warm/hot..... are there two conduits connected to it ?

Hard to tell what's happening here. Maybe red, white and brown ?

 

A high resistance connection will cause heating.

 

This is the box getting hot..... just like it is. Where's the high resistance connection ?
That's why I asked if it was connected with two conduits.

 

There are two independent brown cables in box 2, but I believe only one is actually brown and the other is red but looks brown because it is charred.

On the outlet which gets hot, yes there are two conduits, but one appears unused (or possibly has cables further down the conduit which are not visible).

 

At this point all your wiring is questionable. It pretty much looks like it's going to need to be replaced.

If I were called to fix that the first thing I would do is to pull all the wiring out. It needs to be checked and probably replaced. When you pull the wires out.... you pull an attached string in.

You'll probably need #12 THWN wiring in white, black and red. Comes in 100' coils or on larger spools.

Klein Tools 500 ft. Pulling Line-56108 - The Home Depot

 

I think the conduit may be filled with water (outlets they have been poorly insulated and exposed for years I suspect) and a short somewhere in the system in heating the water and the conduit.

Agree though this all needs to be dug up and properly rewired. Definitely a project I would enjoy undertaking if I had the time but I'll have to leave this one to the pros.

Thanks again Pete and others for the insights and assistance. This was all very helpful and a good learning experience.

I'll keep you posted on the final diagnosis and repairs.

Thanks again!

Maurice