Electric baseboard heat question

[None]

Electric baseboard heat question

Hello. I'm a new homeowner and I'm trying to unlock the secrets of my house :) In my basement we have electric baseboard heaters, 240V. Curious thing is, the thermostat that controls them is a 24V model!

I traced the wires coming from the thermostat to a box attached to the side of my breaker panel. It's a Honeywell box, but that's all I could tell from the outside.

I didn't want to mess with 240V too much, and I haven't had the opportunity to cut the mains and remove the cover, but I did remove the cover enough to see what looks like a beafy relay or contactor or something along those lines.

So, my question is this... what is that box in all probability? Is it really just a relay box in essence? If so, can someone point to a web site that might fill in some of the details for me?

I'm interested in installing those fancy LCD touchscreen thermostats everywhere, and something like this is obviously what I'll need, so I'd like to understand how this is hooked up and what it is (interestingly, nowhere else in the house has this, everywhere else is standard line voltage thermostats, all electric heating throughout the house).

Thanks all!

[Paul Franklin]

Yes, it's a contactor (relay) There will also be a transformer somewhere to supply the low voltage for the thermostat and contactor; it's probably also in the box next to the contactor.

When the tstat calls for heat, it applies the low voltage from the transformer to the coil of the contactor. This causes the contacts of the contactor to close, applying 240 v to the heaters.

Several reasons they might have gone this route rather than using line voltage thermostats. If the tstat is a long way from the baseboards, they may not have wanted to run heavy line voltage wiring the long distance. Or perhaps the current draw of the baseboards exceeded the rating of the tstat.

You're right that this is the setup you need if you want to add low voltage setback thermostats to control your baseboards.

HTH,

Paul

[None]

Thanks for the info Paul! The only part I was a bit confused by... When you said "it's probably also in the box next to the contactor.", did you mean it's probably in the same box as the relay? In other words, did you mean to say "it's probably also in the box next to the breaker panel"? I don't see any transformer anywhere around it (I do have a background in electronics, although not too much experience with electrical wiring, but I could at least identify a transformer if I saw it). Also, what would I ask for at Home Depot to describe this so they know what I'm talking about? Would simply "contactor" do it? Thanks again!

Frank

[RBM]

[HaHaHa]

That box is a relay, though in the size you have it's more commonly referred to as a contactor.

A contactor allows a low-voltage t-stat to control multiple loads simultaniously, or a single load which might be larger than what a normal line-volt t-stat can handle.

Many line-volt stats are rated to only 22 amps. So if I had to control more than that in one common area, a contactor would be the way to go.

[e-mail]