Undersized controls?

[Chrisjohnson]

I'm the "new" electrician at a small factory in Central Ohio. Our production lines use molten salt baths to cure rubber and silicone extrusions. I don't believe the controls are properly sized. I clamped the conductors ( 6 circuits, 480v 3phs) @ 26.5 amps. The contactor is rated @ 40a the overcurrent bkr is 40a and the wire is #8. The devices are operated 24 hrs a day to maintain the molten condition of the salt and they are very warm to the touch. I don't believe continuous duty derating or 60% capacity of the bkr is being applied properly....am I off base?

 

[ptonsparky]

Warm to the touch means almost nothing.

 

[infinity]

With the numbers that you've provided it appears that everything is okay. #8 AWG THHN conductors are rated for 50 amps @ 75° C so with a 40 amp OCPD that's OK. For a continuous load you would size the conductors at 125% of the load current {26.5*125%=33.125 amps} so your #8 is still sized properly. As ptonsparky said warm means little and is probably just the result of the normal operation.

Welcome to the Forum.

 

[topgone]

Warm to the touch means almost nothing.

Yep. If one can touch them, they're fine!

 

[tom baker]

Welcome to the forum!

 

[Jraef]

Yep. If one can touch them, they're fine!

Yep. I get people telling me that their motors are "hot to the touch", and that's always my response. If you don't leave skin behind, it wasn't "hot" as far as the motor was concerned.