Wiring the Bath

I finished up the wainscoting on Sunday after having run out of material on Saturday.  That job is done. The pictur e on the left is two photos stitched together which means that weird bend in the wall is not an architectural feature.

With the carpentry done, is was time to don my electrician's cap and get to work hooking up the receptacles and the radiant floor heat with its programmable thermostat.

If you remember from a previous post (No Cold Feet), I had to fish wires through the wall for the radiant floor heat since it wasn't part of the original plan for the bathroom.  Now I needed to grab power from a nearby box that contains a GFCI receptacle and a switch for the vanity light.  The receptacle and the vanity light were the only services on the bathroom circuit (the overhead light and exhaust fan are on the upstairs lighting circuit) so adding the radiant heat mat on that line was okay.  The mat is a small one that only draws 1.5 amps.  The instructions recommend a dedicated circuit but grabbing power is okay as long as the mat is protected by a Ground Fault Interrupt (GFI).  The thermostat that came with the kit is has a GFI built into it, so I'm all set there.  If I wanted, I could have used the GFCI receptacle as the interrupt as well.

Getting everything hooked up is easy enough but it's often a challenge to get the wires all shoved neatly back into boxes so the switches and receptacles aren't popping out.  If you're not careful getting the wires pushed back in, you're likely to nick the insulation or dislodge one of the wire nuts.

Once I had the thermostat, receptacle, and switch wired, it was time to connect the circuit to the main panel.  This is where the stress level for the DIYer goes up a notch.  I wouldn't even attempt this if I hadn't been given a good hands-on lesson by an electrician friend. One misplaced poke, and that's all she wrote.

Connecting the circuit to the main panel is a matter of hooking up the leads to the neutral bus, the ground bus, and the breaker, all the while keeping it as neat as possible and staying well clear of the main.

It's remarkable how many individual circuits are required for a smallish modern house.  At this point, I'm up to 20 and I still haven't hooked up the range hood, microwave, or dishwasher circuits.  It's getting pretty crowded to work in the main panel, but I'm nearing the end of having to add circuits and having kept it neat, I've kept it accessible.

When I was done adding the bath circuit to the panel, I was ready to try out the heated floor.  I turned the circuit on and went upstairs to check things out. The GFI on the thermostat was tripped and when I reset it, it tripped again. I reset it again hoping that the second trip was a fluke but the interrupt tripped again.  My worst fear was that the radiant heat mat, that was now buried under porcelain tile, had a short in it somewhere.

When installing the radiant heat mat, it's important to continually test the leads for shorts so that you don't end up tiling over a mat that's defective or has been damaged.  I was diligent and did test it throughout the process, but something can always happen, and this time I was afraid it did.

I took a deep breath, however, and pulled the thermostat back out of the wall to re-inspect the hookup. It turned out that I had mistakenly combined the line and load neutral wires.  That would have been okay in another instance but not with this thermostat.  Once I separated the neutral leads, the thermostat and the heat mat worked fine. Whew!

The nights here are getting cool but with the programmable thermostat dialed in, I've got a nice warm tiled bathroom floor to greet me in the mornings.  When the temperature goes to -20 in the dead of winter, the upstairs bathroom might become a popular spot.

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