Question about amperage rating

Below is my draft of a wiring diagram.

I'd like to have my kettle converted to heat up using a Auberins PID controlling a 5500W Camco element.

Am I right in believing that the element will only draw 23 amps? So am I ok to have a 25Amp contactor and SSR?

Does that mean I only need 15 AWG wire?

What is the input rating that my SSR needs to have? 120VAC or 240VAC?

If you could give me a sanity check, I'd appreciate it.

I'd recommend going to 30 amp ratings for all components. Running at 90% of the rating isn't a good idea. My spa is rated at 1500 watts and uses a 20 amp breaker.

Don't know where you got the 15 AWG calculation, that's way low. 20 amp 120 v circuits use 12 AWG and a 30 amp circuit should use 10.

By your diagram, you'd need a 220 volt SSR.

The contactor is probably fine at 25 amps, but you might want to use a 40amp ssr. They are only a dollar or two more, but will be more resistant to overheating since your not as close to it's max amp rating.

There is no such wire size as 15 gauge wire.
I'd also second the recomendation to go 30a minimun for all terminal ratings... You can get 30a contactot with a 120v coil on ebay usually for less than $15 shipped.

In your diagram I don't see a clear path to power your pid. I would recommend having a main on / off switch then a element on / off switch that only controlled the element. The main on/ off switch would feed the pid and the element switch. The element switch would feed the element contactor.

Thanks so much, I really appreciate the feedback.

There is no such wire size as 15 gauge wire.

Click to expand...

I mis-typed. I was thinking 14 gauge.

In your diagram I don't see a clear path to power your pid. I would recommend having a main on / off switch then a element on / off switch that only controlled the element. The main on/ off switch would feed the pid and the element switch. The element switch would feed the element contactor.

Click to expand...

Thanks, I forgot to run some Line 2 to the PID, and I'll look into how to wire a second switch for the PID.

Don't know where you got the 15 AWG calculation, that's way low. 20 amp 120 v circuits use 12 AWG and a 30 amp circuit should use 10.

Click to expand...

I was looking at this chart that says 14 AWG can handle 32 amps. Am I reading it incorrectly? Is it for a different voltage?

http://www.powerstream.com/Wire_Size.htm


With the threat of overheating the SSR, is a heatsink an absolute must? Am I better off to just buy a bigger SSR or do I need a heatsink regardless?


Here is the updated chart... Thanks for the help...

Use #10awg wire. That is what is required for a 30a by the nec. the amount of wire that goes in a control panel is so minimal the price difference is not a factor.

manoaction said:

I was looking at this chart that says 14 AWG can handle 32 amps. Am I reading it incorrectly? Is it for a different voltage?

Click to expand...

a single 14 gauge solid copper wire can probably handle 32 amps for short periods of time, when installed in an area that it can readily shed heat (ie. not enclosed, not in a bundle).

that is not taking into account anything but a single short piece of wire in, say, a test bench setup. for actual, real world, safe and up-to-code ratings, you should never put 32 amps thru a piece of 14 gauge wire.

go by this:
http://www.buildmyowncabin.com/electrical/copper-wire-gauge-amps.jpg