I upgraded couple of exhaust fan flip switches with timer switch(this one) and it went smooth. Now I am trying to do the same with fire place switch but little confused. I opened the switch and look at the wires and these are smaller in gauge compared to other switches. Also, I could not find load wire using multimeter. I have to mention that there is a wall socket right next to fire place and cord from fire place is always plugged into it.

Is the wire gauge smaller because this is like secondary switch and the socket plug is like primary switch? I am also thinking this switch might be a DC switch. What kind of timer switch I should get for this switch?

Here are the pictures of what I am seeing:

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  • @manassehkatz-Moving2Codidact The goal is to choose how long the fire place should run. I press 30 mins button and fire place should run 30 mins and turn off.
    – javanoob
    Commented Aug 27, 2023 at 20:56

2 Answers 2


From you good photos, those wires seems to be low-voltage, low-current signal wires, not meant for 120 VAC or 240 VAC mains! The low voltage is indicated by the thin insulation; the low current, by the thin conductor. This might be considered "bell" wire, for perhaps a 12 or 16 V doorbell.

You'd need the schematic for the fireplace to determine whether the current is DC or AC, and what voltage and current switching requirements are. This is strictly a control circuit.

The easiest timer to install would be a mechanical clock timer, such as used on bathroom fans and heaters. They use no electricity, getting all the power needed from turning the knob. They're designed to fit a standard switch box, and can handle far more current and higher voltage than that circuit need. They're also inexpensive, but don't hold that against them. However, they do "tick", so wind it and listen before buying, if the noise is objectionable.

  • it’s just fireplace, no blower.
    – javanoob
    Commented Aug 27, 2023 at 20:51

It looks like OP needs a timer that you turn on and then the device (in this case, the fireplace) runs for a set amount of time. Electronically doing that typically requires a full AC (e.g., 120V) circuit, but mechanically it can be done in a way that should work with anything - e.g., mains AC (120V or 240V), low voltage AC (e.g., 12V - 24V) or low voltage DC (e.g., 12V - 48V). These are commonly used for bathroom exhaust fans (so they stay running for a while after you leave the bathroom), bathroom heat fans (so they don't run too long) and similar things, but there is no reason you can't use them for a fireplace. Something like the Intermatic SW60MWK:

Intermatic SW60MWK

Picture from Amazon, but also available from Home Depot and other stores. Intermatic has been making timers (of all types) for a long time. While the specifications say "125-277 VAC, 50 Hz;125-277 VAC, 60 Hz", which covers basically the worldwide range of mains AC residential devices, I see no reason it wouldn't work just fine for low voltage AC or DC, up to the maximum of 20A. Actually, if it is DC then there are reasons why it would probably work reliably only at much lower current levels (basically it is harder to switch DC than AC) but based on wire sizes I suspect this is a relatively low current application.

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