who's an Electrician ?

[WURTY]

Here's my problem.

Under my house is a junction where 3 10 gauge aluminium wire connect to 3 ,10 gauge copper wires with wire nuts.

They were all melted.

They connect to my Hot tub.

The tub requires 240 v 24 amps .

Is there some problem going from aluminium to copper by just using wire nuts?

Why would all the connections be melted ??

I'm scared.

 

 

help

[Joe Frickin' Friday]

http://en.wikipedia.org/wiki/Aluminum_wire#Joining_aluminum_and_copper_wires

 

Most likely the connections corroded over time; the increased electrical resistance at the connection (because of the corrsion) caused heating within the connection that got bad enough to melt things.

 

Check Home Depot/Lowes for connectors that are specifically designed for joining copper wire to aluminum wire. I haven't looked for such things, so I don't know if they have them there or not; if not, check the yellow pages for an electrical supply store, where they are more likely to have it.

[Joe Frickin' Friday]

Picture below look familiar? Taken from here, along with this caption:

 

FIGURE 1 - The use of most types of twist-on connectors for pigtailing repairs can lead to hazardous results. This twist-on pigtailing connection (two #10 aluminum wires with one #12 copper wire, in a 20-amp circuit) remains electrically functional in the circuit, but becomes extremely hot whenever a significant amount of current flows. The heat has deteriorated the insulation on both the connector and the wires. A portion of the connector's spring (white overheated section of spring in photo) becomes red hot at current above 12 amps.

[Lawman]

Here's my problem.

Under my house is a junction where 3 10 gauge aluminium wire connect to 3 ,10 gauge copper wires with wire nuts.

They were all melted.

They connect to my Hot tub.

The tub requires 240 v 24 amps .

Is there some problem going from aluminium to copper by just using wire nuts?

Why would all the connections be melted ??

I'm scared.

 

 

 

 

help

 

Wurty,

I had a hot tub one time.

Didn't like the idea of setting in a hot tub with an electric light and a surge protector that kept tripping.

I solved my problem by making a water trough out of it..

[WURTY]

Thanks Mitch

 

I called every electrical supply and they are all closed for the holliday.

 

The pannel has 60 amp breakers and the spa calls for 24 amp so I am guessing thats why the breakers didnt pop when they should have.

 

 

That must be bad right ?

 

[Marty Hill]

Once the water cools, the sheep will love it.

[Joe Frickin' Friday]

Thanks Mitch

 

I called every electrical supply and they are all closed for the holliday.

 

The pannel has 60 amp breakers and the spa calls for 24 amp so I am guessing thats why the breakers didnt pop when they should have.

 

The breaker will only trip if the circuit draws more current than the breaker is rated to deliver; this is useful if you plug six hair dryers into one outlet, or if one live wire somewhere in the circuit somehow gets shorted to ground. Either of these situations threatens the entire length of wire (all the way back to the breaker) with overheating due to excessive current flow.

 

But the problem you have is different. The circuit is drawing approximately the same amount of current it always has, well within the limit of the breaker; it's just that now, some of the energy is getting deposited in that corroded connection instead of in your hot tub. Not much energy, but then the connector is pretty small, so it builds up to high temperature in fairly short order.

 

The only way this particular circuit will shut itself down is if:

 

A) insulation melts off of the hot wires to the point where one of the then-bare live wires shorts to ground (then the breaker opens), or

 

B) the connection melts to the point that the wires fall loose from each other, and current can no longer flow at all.

 

When you redo the connection, inspect the wire insulation for a good distance down each wire, since it may also be heat-damaged. In fact, if this was my house, I'd pop open a few other outlets and switches around the house just to inspect for possible corrosion/heat issues related to the aluminum wiring.

[WURTY]

Mitch that alum wire is only going from the pannel to the hot tub wires. The rest of the house is all copper and no issues.

 

What size breaker should be on the 2 hot leads to the spa. The spa says 24 amps.

[StuGotz]

Wurtmeister.

 

sending you a PM

 

MB>

[Twisties]

My electrician made me install a breaker box rather than join wires directly by any method on a hot tub circuit.

 

I assume mb has you set up straight though.

[Fugu]

Aluminum to copper is a recipe for a structure fire. When I was adjusting claims I saw it repeatedly.

 

As has been mentioned, there's some special connection hardware that's required, key is avoiding corrosion and therefore resistance. I don't know much about the fixing, I just used to read it in fire cause and origin reports from fire investigators....

 

Get some professional assistance (looks like you may have already from mbelectric). If the solution is some geegaw special connector I'd put it on my annual household check list with stuff like smoke alarm batteries, etc.

 

 

[ESokoloff]

Thanks Mitch

 

I called every electrical supply and they are all closed for the holliday.

 

The pannel has 60 amp breakers and the spa calls for 24 amp so I am guessing thats why the breakers didnt pop when they should have.

 

 

That must be bad right ?

 

I would think the best way to fix this would be to change out the aluminum wire to copper.

#10 AWG copper wire is good for 30 amps & I'm sure that the aluminum has a lower rating so I would guess that would be 25-amps.

That would be higher then the required 24-amps but barely.

 

The circuit breaker protects the wire so the 60 amp one needs to be replaced to match the lowest amp rated wire in the circuit.

 

Also you suffered an overheating condition caused by a loose connection(s).

This is not to be confused with an over current condition(unless the melted wire connector(s) allowed the wire(s) to short to each other or to ground.

 

Some good info here.

[Smoky]

I think you should sell that house, and move to Idaho!!

 

Pronto!!

[Ken H.]

Thanks Mitch

 

I called every electrical supply and they are all closed for the holliday.

 

The pannel has 60 amp breakers and the spa calls for 24 amp so I am guessing thats why the breakers didnt pop when they should have.

 

 

That must be bad right ?

The circuit breaker protects the wire so the 60 amp one needs to be replaced to match the lowest amp rated wire in the circuit.

Yes, that’s a key point many people don’t understand. The correct breaker size has nothing to with the device/appliance(s) (hot tub, stove, lights, whatever). The Breaker should be sized to the wire. If the breaker then still trips, the wire is too small not the breaker.

 

No mention as to what gauges of wire were talking about here, but 2-phase 220v (common for a hot tub) wire that would carry 60 amps would be very large in size so my guess is the breaker is way too big for the wire. But someone needs to know the wire sizes and type and do the math.

 

I agree, the idea of replacing it all with appropriate sized copper AND a correctly sized breaker is the best approach. But lacking that there are copper to aluminum split bolts that when used with anti-corrosion compound will make a reliable connection. They will be marked “AU.” But the breaker size issue still needs to be addressed.

 

[StuGotz]

Thanks Mitch

 

I called every electrical supply and they are all closed for the holliday.

 

The pannel has 60 amp breakers and the spa calls for 24 amp so I am guessing thats why the breakers didnt pop when they should have.

 

 

That must be bad right ?

The circuit breaker protects the wire so the 60 amp one needs to be replaced to match the lowest amp rated wire in the circuit.

Yes, that’s a key point many people don’t understand. The correct breaker size has nothing to with the device/appliance(s) (hot tub, stove, lights, whatever). The Breaker should be sized to the wire. If the breaker then still trips, the wire is too small not the breaker.

 

No mention as to what gauges of wire were talking about here, but 2-phase 220v (common for a hot tub) wire that would carry 60 amps would be very large in size so my guess is the breaker is way too big for the wire. But someone needs to know the wire sizes and type and do the math.

 

I agree, the idea of replacing it all with appropriate sized copper AND a correctly sized breaker is the best approach. But lacking that there are copper to aluminum split bolts that when used with anti-corrosion compound will make a reliable connection. They will be marked “AU.” But the breaker size issue still needs to be addressed.

 

Not to get picky here, but let's clarify a few points and some that Ken made, in order that we lead people down the right path for a safe installation:

 

When setting up a spa electrical connection, first read the manufacturers' installation guide. They will tell you what size wire is recommended for the model spa you are installing. And you must follow NEC guidelines, and local building department requirements.

 

That said, wire is chosen with the following in mind,

 

*Spa motor requirements (if not available, read manufacturers UL nameplate for load info).

*Length of wire run (voltage drop).

*Type of wire used. ( Ins rating and CU or AL)

 

Circuit breaker is sized for the wire, not to exceed max ampacity of wire. It is important to closely match the wire size and fuse size to the Spa requirements.

 

GFCI and/or other fused disconnect must be used for spa in situations where spa in not within sight of circuit breaker.

 

>>>>>2 phase is incorrect. Household voltages are 120/240v single phase.

>>>>>UL listed connectors for splicing Aluminum to Copper will be listed as AL/CU

 

MB>

[WURTY]

MBelectric has saved the day.

Wires are repaied and Spa is running .

Just burned a cheap cigar while soaking my huge A$$.

 

Thanks again Mark