Tell me what's up here...

[e-tek]

My Hot Tub flipped it's breaker last night and when I flipped it back on I smelled heat. Today it was off again, so I turned it on and got in. About 30 mins and it tripped. Got out and took a closer look, finding this -

The 50Amp breaker was warm and the Red wire was burning HOT! So hot it had melted the wire to the lug and the lug through the housing. I turned it off at the main panel and pulled it.

So why?

(And before anyone goes off with the near-death scenarios - I'm fine.....)

 

[LXCam]

The connection was lose. Could have been the wire, or the lug to internal bussing or even the contact points, but sumtin was lose.

 

[Radio Ron w4ron]

Yep that's exactly right, seen it a million times.
Keep the screws tight, as tight as you can turn them.

 

[Aceman]

Yep that's exactly right, seen it a million times.
Keep the screws tight, as tight as you can turn them.

That's horrible advice.

I do this for a living, follow the manufacturers torque recommendations and wiggle the wire in the lug as you tighten it to help get the strands to lay flat. Doing that will eliminate loose connections.

 

[G_P]

Yep that's exactly right, seen it a million times.
Keep the screws tight, as tight as you can turn them.

Cranking them down super tight like that will lead to stripped out threads on the terminal. Lots of those screws and the terminal they screw into are soft brass and will strip easily. Then your whole component is junked. (Been there done that)

When it comes to high amperage relays or anything with contacts in it its a good idea to periodically look at the contacts to see if they are getting burned up.
If its not badly damaged a small file can be used to clean up the contacts and lots of industrial type equipment has replaceable contacts. If you bring the part to an electrical supply house they can tell you if its rebuildable or not and if parts are still available.

In your case with the plastic melted like that its time to replace the whole unit.

Sent via carrier pigeon.

 

[G_P]

Messed up. Deleted.

 

[e-tek]

Thanks guys. Spot on as usual. The middle wire came out fairly easily. Another $120 repair.....

Like EVERY-frikken-THING, the Hot Tub requires constant upkeep (aka time sucking POS). If I didn't NEED an hour of quiet-time every night in it's soothing, massaging, warm arms, I wouldn't bother!

 

[ratdoggy]

If I didn't WANT an hour of quiet-time every night in her soothing, massaging, warm arms, I wouldn't bother!

Fixed it for you

 

[ddawg16]

They don't call the 'soak and pokes' for nothing.....

 

[MTW]

I 2nd that motion

That's horrible advice.

I do this for a living, follow the manufacturers torque recommendations and wiggle the wire in the lug as you tighten it to help get the strands to lay flat. Doing that will eliminate loose connections.

Terminations heat up and expand with current flow. Especially with aluminum lugs and setscrews as shown in the picture. When you make it as tight as you can, and then it expands, guess what?

It strips the threads off of the screw or lug, resulting in a permanently loose connection. Even if you try re torquing the threads are damaged and it will no longer hold it's torqued setting.

Follow the advice given above, especially the wiggling part. And if you don't have a torque screwdriver, tighten fully while wiggling, then loosen and re-tighten to a medium tightness. Never leave it as tight as you can make it, unless you want to replace it later.

 

[e-tek]

$225 for the replacement.

Seems expensive...but that's only 3 full body massages.

And it wouldn't even pay for one - with a happy ending....