My 120v Hot Tub started burning/melting the power cord last night.

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
Ive had this hot tub going for a few months already (it was used). replaced the pump and heater and its been awesome.

Last night however, I was cleaning out my yard and I smelled something burning. Couldnt figure out what it was so I kept cleaning.

Then my girlfriend comes out and says "is something burning"?

I grab the cord and its hot and the thick part that surround the prongs is starting to melt a bit.

The funny thing is that Ive always set it to 104, but in the last 2 days i turned it down to 102.

Does anyone know why its doing this? The only thing that I can think of is that I used a "ground" from the Pump to the post (as it should be), but this ground cord came from a 220v Fridge plug. So there are multiple wires making up the ground cord. Originally it came it a thick copper wire, just one big one. Could this be why its burning?

I unplugged it overnight because my infant daughter sleeps about 8" on the other side of that same wall.

Any help would be appreciated.
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
Here are a a few images. I added that yellow extension unit in case it ever overheated since my daughter is a foot away.

Pump and heater are about 2 months old. Has been working perfect since.

See the green ground cable thats going from the pump to the post/box, its not original, its what I used to replace the shorter ground wire from the old pump.

You actually helped me on this thread about 2 months ago: New heater came in. Still not getting hot.20201009_194826.jpg20201009_194840.jpg20201009_194840.jpg20201009_194952.jpg20201009_195035.jpg20201009_195059.jpg20201009_195118.jpg20201009_195146.jpg
 

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Mdragger88

Bronze Supporter
Jun 1, 2018
1,334
Hernando, Ms
I just saw a full pic of the set up on your old thread. It looks like power cord is too small (standard 16 gauge) If the run is longer than 10 ft I would use @ 12 gauge cord. Otherwise you could go with 14 gauge. (Notice that all the other wires in the box are larger than the power cord wires) If it has been wired this way it’s probably why the pump burned up before.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
7,176
Central California
Those extension cords are way undersized for the load. Typical "garden variety" extension cords are 16 gauge, which are rated for about 10 amps. You've got a pump motor that appears to be pulling 15 amps. That's not counting the heater. You've also got a fuse in there rated at 30 amps. I don't know enough about spas, and certainly not enough about yours, to determine how those amp ratings would be affected by whether the whole thing is wired to 120V or 240V, but short version, you've got a real electrical hazard going on (obviously). I'm not sure 14 or 12 gauge would be enough. Some of it was certainly your doing, but some might have been from the previous owner, too. Who knows. You need to hire an electrician that knows spas, or a spa installer/repairman, probably both, to both fix the internal and external wiring mess and provide a proper electrical service and breaker (GFCI) of sufficient amps.

You have at least two very dangerous issues. (1) The fact that there is wiring that can't support the current draw and (2) that a breaker didn't pop before it melted. Inches away from your kid's bedroom? Please don't DIY this, or seek more advice from an Internet forum, that's already backfired (literally). Call in a pro and have it done right.
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
The old owner did the conveison from 240v to 120v himself. Used that orange "cheap" cord.

That cord is 24ft long with that attachment.

I upgraded the ground to the solid copper cable. Then I changed the plug and used an 8ft heavy duty cord. I believe it's more HD than the orange one that burned out (and shorter).

When it got hot, the piece that connects to the house wasn't melting, only the female side that was hooked up to the old orange 24ft cord.

I'm currently heating it up and re-testing it. I'm definitely going to have someone come look at it and test. But from what I have dug up, the cord wasnt HD enough, it was too long and it had an added in between piece. If it doesn't over heat, I'm going to buy a 12 gage, 6ft or 8ft Unit with that "tripping" piece built in.
 

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jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
Those extension cords are way undersized for the load. Typical "garden variety" extension cords are 16 gauge, which are rated for about 10 amps. You've got a pump motor that appears to be pulling 15 amps. That's not counting the heater. You've also got a fuse in there rated at 30 amps. I don't know enough about spas, and certainly not enough about yours, to determine how those amp ratings would be affected by whether the whole thing is wired to 120V or 240V, but short version, you've got a real electrical hazard going on (obviously). I'm not sure 14 or 12 gauge would be enough. Some of it was certainly your doing, but some might have been from the previous owner, too. Who knows. You need to hire an electrician that knows spas, or a spa installer/repairman, probably both, to both fix the internal and external wiring mess and provide a proper electrical service and breaker (GFCI) of sufficient amps.

You have at least two very dangerous issues. (1) The fact that there is wiring that can't support the current draw and (2) that a breaker didn't pop before it melted. Inches away from your kid's bedroom? Please don't DIY this, or seek more advice from an Internet forum, that's already backfired (literally). Call in a pro and have it done right.
Thanks for the info. I did have someone come take a look at it when I couldn't figure out why it wasn't heating up. They determined it was the pumps low speed. I then purchased another pump for 120v set up.

I've left the hot tub on for 2 months, set to 104 and used it regularly about 4-5x per week. That cord has always worried me because it looked cheap, but the tech didn't determine that to be a problem so I didn't think about it, but then again he was there to find out why my spa was shutting down and not heating up.

I'm going to keep testing it and buy a 12gage plug with a built in "tripping" unit.
 
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jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
It's Ben running for 4hrs and hasn't overheated. It's at 99 degrees now and set to go to 102. I touched the cable and plug, they feel warm, but not hot. Seems to be working fine
 

Mdragger88

Bronze Supporter
Jun 1, 2018
1,334
Hernando, Ms
What gauge is “heavy duty”? It should be stamped into the cord. My 110v hot tub has a 14gauge 10ft cord w/ built in gfci from the factory- not sure what the motor & heater are rated. The 24ft voltage drop (longer run adds more resistance which creates heat) w/ too small of wire = melting.
That is why the wires need to be sized properly so they don’t burn up or burn up the motor before the overcurrent device trips. It definitely wont hurt to use a 12 gauge or if it needs to be a longer run get a 10.
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
What gauge is “heavy duty”? It should be stamped into the cord. My 110v hot tub has a 14gauge 10ft cord w/ built in gfci from the factory- not sure what the motor & heater are rated. The 24ft voltage drop (longer run adds more resistance which creates heat) w/ too small of wire = melting.
That is why the wires need to be sized properly so they don’t burn up or burn up the motor before the overcurrent device trips. It definitely wont hurt to use a 12 gauge or if it needs to be a longer run get a 10.
It's 14 Guage, 6ft long.

My brother replaced the old unit that goes into the wall. This new one has a waterproof cover and that trip button (I think it's a gfci)?
 

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jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
14 gauge wire should only be used up to 15 amps.

The data plate you posted above says it will draw 16 amps at 120V.

The wire getting warm is not a good sign. Wire heat is cumulative and it will fail in time. You should be using 12 gauge wire at a minimum.
Got it. I'll order one on Amazon. Do you think this one will do the trick? I don't see the Guage info anywhere

Amazon.com : GFCI Cord Replacement for Hot Tub, Spa & Pool - 120V/15A Inline Style : Garden & Outdoor
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,368
Tucson, AZ
You’re potentially drawing 16amps on an outlet that’s only designed to deliver 15 amps. Is that outlet the only one on the circuit to the CB panel or are there other outlets with things plugged into them on the same circuit? The cord is the least of your problems - if you draw too much amperage on wires running in your walls, you’re going to cause a house fire. You can also potentially cause arcing to occur inside your wall which GFCI outlets can’t detect. Arcing causes wall fires. And finally, if you have that GFCI wall outlet then there should be no other GFCI outlets on that circuit. You’ve got yourself a serious set of code violations there any one of which would void your home owners insurance paying you out for possible fire damage.

Proper wiring is to have an electrician run a dedicated circuit to that hot tub. It should not be plugged into a wall outlet. You need to get a qualified electrician to give you an estimate for a proper installation....your child and your home are worth the cost.
 
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RDspaguy

In The Industry
Mar 21, 2020
914
Cabool, Mo
That control is designed for 120v operation on a 20 amp circuit which requires #12 wire and can be plugged in to a DEDICATED circuit (which means nothing else on the breaker). The gfci protection can be on the cord or at the plug or breaker and must be at least 5ft from the spa. You cannot use extension cords.
 
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jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
That control is designed for 120v operation on a 20 amp circuit which requires #12 wire and can be plugged in to a DEDICATED circuit (which means nothing else on the breaker). The gfci protection can be on the cord or at the plug or breaker and must be at least 5ft from the spa. You cannot use extension cords.
Do you mean that the spa must be 5ft or the cord needs to be 5ft? The chord is 6ft and the spa is 3.5ft away from the wall to be exact.

I'll check into the breaker being dedicated tomorrow. If I'm lucky, it will be. But not counting on it so I'll start thinking around it.

I'll get a 12 gage and I'm not using any extension cords anymore. I was running my projector off that outlet as well but I can easily change that to another location that doesn't run off the same breaker.

The only thing I'm wondering about is, assuming I fix all the above issues, how do I make it 20amp? That new waterproof wall unit is 15amp. Do I need to replace it with a 20amp unit? I didn't bother looking for one of those but I can go back and find one that is 20amp instead of 15
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
7,176
Central California
That existing outlet on the back wall can't be used for your tub. You cannot just change out the GFCI outlet from 15 to 20 amps. The wiring in the wall that supplies that outlet is not of the proper gauge to support 20 amps. And it is very unlikely that outlet is the only one on the circuit breaker. It's more likely that there are as many as a dozen or more outlets on that circuit, probably including all the outlets in your kid's room.

You need to have an electrician run a dedicated line from your circuit breaker box to a location 5' away from where you want the tub. If you're lucky, there may be access through the attic or crawlspace that would allow the installation of the outlet in the wall. If not, it'll have to be a conduit run, along the outside of your house, from the breakers to the new outlet. The new wiring, the new dedicated breaker and the new GFCI outlet will all be rated for 20 amps. Then you can use the existing outlet for your projector (though you may have to relocate the tub if your building code doesn't allow any electrical outlet within 5' of the tub).

In addition to that, you need to install a proper 20 amp pigtail (cord) from the tub to the new outlet, and clean up whatever you and the previous owner did inside the tub that is unsafe or not to code.

If there would be some performance advantage to running the tub off 240V, then the electrician could just as easily run a dedicated 240V service to the tub.
 
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ajw22

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TFP Guide
Jul 21, 2013
20,358
Northern NJ
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