controlling 2 electric heaters with limited amps available

[The Cobbler]

got an odd or unique situation on a project I'm working on for a family member
limited amps available; 30 amp @ 240 / "borrowed" from neighbours via 10/3 cord need some temp heat in the project . need to heat the main floor to a comfortable working temp, say 65°. the basement needs a bit of heat as well .
I have construction heaters that are 4800 watts . also need some power for tools and lights . place should be pretty much all rewired over the next few months .
I would like to run the main floor heater to maintain a reasonable temperature but also dump some heat into the basement as well . So far it has been quite mild here, but after Christmas, who knows. I want to be prepared .
I am thinking of this for a solution ... while the main floor is wanting heat, the basement can't be heated ( not enough power) , but when the main floor is satisfied, the basement can use some of that power to get some heat .
I was thinking a DPDT t-stat , set to 65° to run the main floor heater ( built in heater t stat would be set higher than 65°) , then when it is satisfied for heat, it shuts off & closes the contacts for the basement heater, which would be controlled by the onboard Tstat
does this make sense? is there an easier solution that I'm not thinking of ?

 

[dave*99]

; 30 amp @ 240 / "borrowed" from neighbours via 10/3 cord need some temp heat in the project . need to heat the main floor to a comfortable working temp, say 65°. the basement needs a bit of heat as well .
I have construction heaters that are 4800 watts . also need some power for tools and lights .

If you truly have 10/3 cord --- you don't have a neutral. You need a neutral to power 120V tools and lights.

 

[Lassen Forge]

My other half and I were just talking about this, as we have a similar situation for my new shop... I have a 25 amp feed 230V for the shop. I need to get a heat source to warm it up a bit for the winter, but I also have to worry about things like lights, the odd power tool, and the ultra small (10l) hot water heater for the sink. And have lights.

I think it's going to be playing musical chairs - turn on the space heaters, shut off the HW circuit (not that I need 24/7 hot water out there), and I should be fine. If I DO need hot water I don't need to have the heater(s) running while the HW heater is doing its thing. Rob Peter to have Paul pay Mark by way of Joseph...

As long as I don't have EVERYTHING going at once I should be fine.

 

[BrandonV]

Should be able to do that with a relay. My biggest concern would be just to make sure there are no delays anywhere with the heaters (e.g. call for heat is cancelled but it still runs for 30 seconds/etc.).

 

[Bert_]

I'm not sure what outside temperatures you're expecting. I think you'll find a basement needs very little heat to stay above freezing, even 50 in a basement takes very little

 

[fitter30]

Heater in the basement with a fan blowing hp the stair well

 

[ipgenie]

Parallax ALS20 Auto Load Shed Relay Module https://www.amazon.com/dp/B00NUKJKLW?tag=atomicindus08-20

I used one of these to automatically shed a lower priority load when a high priority load demanded power. You would need a 240v model but it is very hands off in use.
I my case, it's in an RV and if the lower priority electric water heater is heating and the microwave is started, the device switches off the water heater while the microwave is running, then switches the water heater back on when the microwave is done.

Probably cheaper and simpler to just set it up with the DPDT thermostat in your case though.

 

[The Cobbler]

If you truly have 10/3 cord --- you don't have a neutral. You need a neutral to power 120V tools and lights.

good point and my bad. I will have 10/3 romex running to the house into the basement to a 6 breaker sub panel . the heaters are powered from 10/3 . it is tied to a 30 amp double breaker next door .

 

[theoldwizard1]

O was thinking a DPDT t-stat , set to 65° to run the main floor heater ( built in heater t stat would be set higher than 65°) , then when it is satisfied for heat, it shuts off & closes the contacts for the basement heater, which would be controlled by the onboard Tstat
does this make sense? is there an easier solution that I'm not thinking of ?

Makes PERFECT sense, but I doubt you ever find DPDT thermostat !

Use a 120v "on-line" thermostat powering a 120v (coil voltage) DPDT relay. Look for one with 50A contact rating.

If the basement heater does NOT have a built in thermostat and it is 120V, use a second inline thermostat to shut if off above 50F.

 

[The Cobbler]

doubt you ever find DPDT thermostat

they are available on Ebay. a bit pricey but...

 

[theoldwizard1]

they are available on Ebay. a bit pricey but...

Inline t-stat and relay. Probably much cheaper !

 

[The Cobbler]

so a double throw relay ?

 

[dave*99]

Connect this timer to power both heaters. It's DPDT. Use the internal thermostats in the heaters.
One heater powered by the NO contact and the other by the NC contact.

https://www.amazon.com/Industries-TU40-Universal-Multi-Volt-Electromechanical/dp/B0057XZDIY/?tag=atomicindus08-20

 

[wyliesdiesels]

good point and my bad. I will have 10/3 romex running to the house into the basement to a 6 breaker sub panel . the heaters are powered from 10/3 . it is tied to a 30 amp double breaker next door .

you said this feed is "borrowed" from the neighbors. does that mean the NM-b (aka Romex) will be running outside, on the ground or underground? if so that is not permitted and not a good idea

 

[walta]

You could wire this relays coil across the upstairs heaters element so the relay turns on with the heater and use com and NC too open and turn off the down stairs heater so the downstairs heater could only come on if the upstairs heater had reached it set point.

I don’t much like the idea of opening the heater and connecting the relay. If the budget allows this current relay could monitor the upstairs heater and switch the power relay controlling the down stairs heater.

https://www.functionaldevices.com/product/rib02p30-nonc/

https://www.amazon.com/Current-Self...e-Normally/dp/B092M7PB8W?tag=atomicindus08-20

 

[dave*99]

I don’t much like the idea of opening the heater and connecting the relay

I agree. Portable heaters sometimes use high temperature insulation on internal wiring. It’s not the best place to mess around if you don’t have the correct wire.