A spliced hotwire (black) to the pump burned in breaker box

[run53]

My FIL called me because his pool pump stopped working. When i got there to check it out, I noticed that there was no power getting out to the pump. I then checked the Breaker box to see if the circuit breaker had tripped, but it was ok. After a couple of hours of tracing his wiring and using my multi-meter to try to understand his circuit, I came to the conclusion that there must be an open somewhere between the timer and the pump.

The first thing i though of was an animal eating through the conduit and chewing the wire. When that didn't seem likely, I finally decided to open the Circuit Breaker box to take a look. The first thing I saw was the hot wire (black) going to the Pump was spliced (with a wirenut) inside the breaker box. The load wire coming from the timer was spliced to the black wire that headed out to the pump. This wirenut connection was totally burnt to a crisp. Not only that, but both spliced wires were burnt about 2-3 inches. I suspect that the splice burnt due to a bad connection?????? Probably heated up each time the pump was turned on. I am surprised there wasn't a huge problem as a result. I hate to think about what could have happened.

So, my biggest question, is, what, if anything can protect against this dangerous situation. This circuit is protected in the breaker box with a GFCI breaker, which, when tested, trips as it should. I know that GFCI's measure the difference between the current on the black (line) and white (neutral) and trip if there is a 4-6ma difference ( so it really only protects if the frame of the appliance or ground, is exposed to the hot wire, thus sucking up some of the current before it flows to the neutral wire). I think i can understand why the GFCI would not trip (current going thru the bad splice is the same that returns to the GFCI on the neutral side).

Is there anything that can protect against this type of failure (other than making sure the splice is good)?

 

[CraigMW]

Re: A spliced hotwire (black) to the pump burned in breaker

Don't use a wire-splice. Just run new wires to the pump and make sure they are rated appropriately for the amperage and distance. For example, if you are using a 20A 2P breaker, make sure that both load wires are 12 ga. or larger copper wires. I wound not suggest using any splices if you don't have to. I think your guess is right regarding the failure. Wire nut splices can develop resistance over time. This resistance leads to heating and can eventually cause the connection to heat to the point where the wires and wire nuts will burn out. A GFCI breaker simply tests for different current between the load and neutral wires. It would see this added resistance equally in the load and neutral (since it is not a ground fault, or leakage of current to ground). Thus, it would not trip. This could be prevented by an arc fault breaker, but I'm not aware of anyone using these for pool pumps. Just run the appropriately rated wires and avoid splices.

 

[duraleigh]

Re: A spliced hotwire (black) to the pump burned in breaker

I'm w-a-a-a-y out of my pay grade answering electrical questions but it would seem to me a splice inside a breaker box might be a code violation.....especially a wirenut splice.

 

[Bama Rambler]

Re: A spliced hotwire (black) to the pump burned in breaker

They make arc fault circuit breakers that handle that but you'll need a combo afci/gfci for the pump.

Just as a sde note: The NEc requires all new constructions to have acfi all in bedroom outlets.

 

[scooperhsd]

Re: A spliced hotwire (black) to the pump burned in breaker

I'm w-a-a-a-y out of my pay grade answering electrical questions but it would seem to me a splice inside a breaker box might be a code violation.....especially a wirenut splice.

A splice in the box is not technically a violation - but it is sloppy. But it beats an outside the panel junction box.

OTOH - I wouldn't want to do a splice on a high wattage item such as a pool pump in the breaker box.

And I am not an electrician.

 

[Ohm_Boy]

Re: A spliced hotwire (black) to the pump burned in breaker

Splices are common and legal, but occasionally, they are faulty. Your suspicions about the heating during current flow is dead on, and that would be the cause of the failure. The 'good' wire nuts have a wound spring cone inside, made from a steel wire with a square cross-section. It is designed to bite into the copper conductors and creates a connection which is supposed to get better with age - it actually creates a better connection than soldering. The cheap-o wire nuts have a solid metal cone with some scribed 'thread' lines or no metal insert at all, and can only try to squeeze the copper wires together inside. These are way more susceptible to loosening from heating/cooling cycles. The same can happen if the wire nut is not tightened well.

I've also seen a handful of bad installations where the wires were not inserted into the wire nut evenly, with one sticking further in than the other, and the stripped ends didn't really line up. This made for a very tiny overlap where the copper actually touched, created a bad connection and over a long time of heat cycles, burned to a crisp.

Wire nut connections are supposed to be within an electrical box, and the breaker panel is certainly an electrical box, so it can be done, but as you learned, it is frustrating to have to find a failure like this. I've found them within wiring ducts and inside conduits. THOSE were tough.

As for protection, the circuit breaker will catch it if the hot side were to actually touch the exposed housing, conduit, switchplate, etc. (**ASSUMING** a properly grounded installation) hopefully before anyone can touch it. An arc-fault detector would have shut it off before it could fully separate. A ground fault interrupter should catch it if someone actually managed to make contact with it.

For what it's worth, it can be more confusing when it happens on the neutral side. Testing w/ a meter shows voltage at the motor, and the motor checks good, but it won't run. Frustrating, unless you know to check for it.

Sorry - rambling again.

 

[run53]

Re: A spliced hotwire (black) to the pump burned in breaker

Thanks for all the responses. I really wanted to confirm my suspicions of what caused the issue.

I clearly understand that running a new wire out to the pump is the best fix, but it's not my pool and my FIL wanted a quick fix to get his pump running again (pool was getting cloudy). So I re-spliced after cutting back the damaged wire. I did have to run a new black wire from the timer (load) to the breaker box because I had to cut too much of the damaged wire off.

After seeing this installation (which was done about 25 years ago), I would concur that it was a sloppy job. To complicate things, the electrician used stranded 14-2 wire to run out to the pump (it's a 110v circuit, not 220v). I HATE working with stranded wire! So, I had to splice a solid copper to a stranded copper in the breaker box. To do the splice, I wrapped the stranded wire around the solid copper, then put a fish hook (bent the solid over the stranded) and capped it with a yellow cap. It seemed pretty solid.

Maybe in the off season (he will close the pool on Labor day) I should consider running a new wire out to the pump. It's about an 80' run with a couple of twists and turns as it exits his basement. I've never pulled wire through conduit before. Any idea how difficult that might be?

 

[Bama Rambler]

Re: A spliced hotwire (black) to the pump burned in breaker

Pulling wire through a conduit can be easy or extremely difficult. If you're just pulling one circuit and the conduit is reamed and installed correctly and 80' pull isn't bad at all. Be sure to use pulling lube.

 

[run53]

Re: A spliced hotwire (black) to the pump burned in breaker

Yep...only one circuit in the conduit (assuming I pull the existing one out). I would think the best way to pull the new wire is to use the existing one as a tow, making sure the new wire has a STRONG connection to the old one

Thanks

 

[Bama Rambler]

Re: A spliced hotwire (black) to the pump burned in breaker

That's the way to do it.

 

[CraigMW]

Re: A spliced hotwire (black) to the pump burned in breaker

It might be better to run a sub-panel from the main breaker to the pool equipment pad at some point. If the pool is 25 years old, it might have a metal conduit. In that case, I bet it's all rusted out and the conduit will have to be dug up and replaced. The hard part of this would be digging the appropriate trench. At that point, you would probably want to run a 220V line (with red, black, white and green 6 or 8 ga solid copper wire rated for wet environments) to the pool sub-panel (itself a main lug with separate and unbonded grounding and neutral bars). Insert appropriate 40-60A breaker in the main panel (depending on wire ampacity) and you are good to go.

I would first see if you can tug on the wire to move it through the existing conduit. If it works, you might be able to pull new cables through it. But, I would still add a fresh sub-panel for upgrades. Also, the pool motor circuit (and definitely the lighting circuit) should be GFI protected. I think splicing the stranded wire to a fresh one from the breaker is okay for a temporary fix, so long as the wire nut was used correctly. BTW, what is the current draw of the pump? At 110V, it will need to pull plenty of amps and 14ga seems a bit light to me. What is the breaker rating? 14ga should be protected by a maximum 15A breaker, and this might need to be downrated for an 80 foot run.

 

[run53]

Re: A spliced hotwire (black) to the pump burned in breaker

The conduit is indeed metal. At least the section I can see in the basement. It goes through the foundation as metal and the run up to the pump outlet is also metal, so i would assume it's metal all the way, underground.

This is a very basic installation. The only thing serviced by the circuit is the pump. Out at the pump, there is a metal box that houses a switch (that controls the pump) and the pump receptacle. That's it.

This circuit runs back to a 15A GFI breaker in the box (which is also tied to an Intermatic T101 timer). The load and neutral wires are both spliced in the breaker box between the timer and the breaker and the actual circuit.

Not sure the current draw on the pump, but I will check it out when I go over there next time. Maybe the draw is just too much for 14 Gauge and over time, that and a bad splice caused the overheating.

I think adding a sub-panel would be overkill for what he has out there. My FIL is 81 years old and their pool doesn't get much use anymore as we all have our own pools now. I just try to help him out with it. A couple of times he mentions filling it in , so I know he wouldn't want to add any more expenses. I just want to keep it safe for the years of life it has left.