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Discussion Starter · #1 ·
Description- there is two heaters ran off of one power feed (30amp breaker) #6 wire. The wire is number 6 cause of the distance to the load.
One heater draws around 16 amps. Control is 24 volts that cycle the contactors one on at a time.

If two magnetic contractors are installed to control the heaters it’s easy to make sure one is one at a time by using NC contacts on the contractor. The control wire of heater A go through heater B NC contacts so if heater B gets stuck closed then heater won’t turn on if it gets the signal to operate.

It is really simple and my question. In this process of one heater is working everything is correct. In the off chance a contactor gets stuck the breaker would have around 32 amps.

Should a person be concerned about the contactor sticking and putting 32 amps on a breaker. As an electrician the possibility of 32 amps on a 30 amp breaker should be avoided if possible.

I know I’m thinking into to it to much and it’s simple wonder what other people thoughts are.
 

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Bilge Rat
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32 amps on a 30 amp breaker might cause it to trip after a while, and it might not trip at all with such a small overload.

In any case, it will very likely not burn anything up.
 

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Discussion Starter · #5 ·
No interlock just a thought. Seeing the odd breaker burn up cause of short circuit or over load.

Is interlock in this situation pointless or is protecting a beaker from a possible over load good practice m?
 

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No interlock just a thought. Seeing the odd breaker burn up cause of short circuit or over load.

Is interlock in this situation pointless or is protecting a beaker from a possible over load good practice m?
I’d would do it if your worried especially since ots
Not that hard to do
 

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Sounds like a complicated way to control a couple of simple heaters. If this is mission critical equipment, then look at it the same way as an alternating pump controller, pump a runs, pump b runs, pump a runs, etc. if pump a or pump b cannot keep pressure / level (in your case heat) then they both run.

Your "level switches" are your TStats.

Cheers
John
 

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What about a line voltage thermostat which can control heating and cooling because it is a single pole double throw? I know that supply houses and Home Depot used to carry these but I haven’t even looked at thermostats in years.

Then, when your primary thermostat for heater a is satisfied and turns “off”, it actually powers up the “cooling pole “which can then be used to power the thermostat for heater B.

Whenever a thermostat a calls for heat it will turn off B whether it’s on or not.
this is exactly the same way an electric water heater works with two elements. The top element takes precedent, but when it is often satisfied power is applied to the lower electric element and thermostat.

This way you do not have to deal with contactors, relays, and a whole bunch of things that can fail.
 

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Are they baseboard heaters?

I'd do as @emtnut said and change the breaker to a 40.

Voltage drop isn't much of an issue on resistive heaters like baseboards, you'll just get slightly less heat out of em if you run 228v rather than 240v.
 
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