Salt Lake City winters can get cold as you can see by the footsteps in the snow at my studio door.  Installing heaters to the building are a necessity.

NOTE:  If you do not understand how to do wiring, get someone with the knowledge to help you.  A mistake here can be fatal or burn you place down.  These are not instructions but an example of what I did.  I assume no liability for what you do or don’t do.

With a cement floor and wall, some sort of frame was necessary to hold the baseboard heaters in place so they didn’t tip over.  At some time in the future, an insulated 2×4 wall will be built and the heaters will have to be moved farther out.  The frame was a temporary solution.

I used 2×4s sitting on their edge to attach small rectangles of OSB (oriented strand board or waferboard).  Paralell 2×4s next to the wall supported the other side of the rectangles while I used a brad nailer to attach them.  Then I flipped over the 2×4s and attached rectangles on their edge against the 2×4s.  Those would be where the heaters would be attached.  I used panhead screws to attach them.

Between each heater would be a junction box that held the conduit on which I attached the thermostats.  Wires between the heaters would also pass through the junction box.

I started at the electrical panel.  The first step was to turn off the breaker outside the building where the meter runs.  FORGETTING THIS STEP CAN BE FATAL.  With the power off, I could begin working.

I ran a piece of conduit from the panel down to the junction box in the corner at the end of the first heater.  I used a conduit bender.  It can be done by hand but if it kinks, you won’t be able to get your wire through it.

Since I was running 3 heaters at 10.4 amps each, I needed a 40 amp ganged breaker which is used for 220 volt circuit.  Technically, it is 230 volts but 110 volts is easier to say than 115 and doubling it becomes 220.  Yeah, it’s dumb but no dumber than having a hot wire (black) and a common or ground (white).  With AC, they are both hot and can kill you.

For wiring, I needed 8 gauge wire.  A single heater could run on 12 gauge which carries 20 amps.  2 heaters is just over the limit of 20 amps so you need 10 gauge.  And 3 heaters bumps you up to 8 gauge.  It is expensive and stiff and will set you back a little over 60 cents a foot.  3-wire cable is available but that is way expensive and difficult to handle.  I used black for both sides of the circuit.  For ground, green or bare copper can be used.

It is sometimes difficult to understand how you get 220 volts from a panel. That is the voltage fed to electrical panels through 3 wires, the third being a common.  From one wire to a common is 110.  Between 2 wires without going to a common is 220 volts.

In the photo, you can see the 3 wires coming in through a pipe in the lower left corner.  In the center of the photo, there are 2 metal bars with clips sticking up in the middle.  A wire is connected to each one.  So common to the bar on the left is 110 volts.  Common to the bar on the right is 110 volts.  And there is 220 volts between the 2 bars.  The breaker clips on to each bar which is why there are 2 breakers ganged together.  The 2 wires coming off the breaker have 220 volts across them and below the breaker is a bare copper wire for ground.

You may notice the extension cord hanging from the plug.  A good safety measure is to connect a light to the panel.  Have it turned on when you go turn off the power.  When you come back to the panel, the light should be off.  If not, the panel may still be hot and dangerous.

When handling the baseboard heaters, be aware that there are sharp edges where they punched out holes for the wiring.

I was feeding wire through the heaters and when  I got to connecting wires, I noticed blood on the heater.  It was my blood.  You might be wise to wear leather gloves.

Another thing to watch out for is getting the insulation on the wiring cut by the sharp edges.  This could cause the electrical circuit to short out when the power is turned on.

 

The next photo shows the electrical connections for the thermostat and the heaters.  The blood will be cleaned off when the wires are tucked inside.

Electricity is fed to the thermostat from the blue wire nut on the right.  The third wire goes to a 12 gauge, 3-wire cable that feeds the third heater.  This only carries 10.4 amps of its 20 amp capacity.

The wire returning from the thermostat goes to the red wire nut on the left.  It feeds the heater on the left and a 12 gauge white wire going to the heater on the right (10.4 amps) which is the middle yellow wire nut.

The return from the heaters, black wire on the left and black 12 gauge wire on the right on far right yellow wire nut  and cable from third heater collects the returning power and sends it to the panel using the blue wire nut on the left.

The next photo shows the wired heaters along the west wall of the studio.

On the floor are my knee pads, an important tool for working at floor level.  There is also a pair of aviation snips (green handles) that makes cutting the heaviest wire a breeze.  The hammer is used with a screw driver to open the knock outs for wiring.

So it’s all hooked up.  I turn on the power and push the circuit breaker to on . . .

Bam!  Sparks and smoke came from the circuit breaker when I turned it on.  That was startling.

I turned the power to the panel off for my investigation.  I tested for a short between my wires coming off the circuit breaker.  Open circuit.  No problem there.  Everything was wired correctly.  I then check each wire with ground.  Sure enough, one wire had a ground short.

I was frustrated enough that I quit for the day.  I was expecting to have to pull everything apart trying to find the wire that might have a cut in it.  Those sharp edges did a number on my hands.  Why not the wire?

When I checked for a short on the wires from the circuit breaker I got nothing but an open circuit.  I checked the wiring and everything was connected correctly.

I opened the metal cover on the junction box at the end of the conduit.  There it was.  The screw that held down the cover had pierced the insulation on a wire and created a short.

You can see the burn mark on the wire.  There is also residue from the smoke on the wires and the cover laying on the floor.

I told you it was stiff wire!  The screw couldn’t push it aside.

With repairs made, the heaters are working like a charm.  But one question remains.  How long will it take to heat the building?  Is 7500 watts sufficient?

Stay tuned.

– Rich Pulham

This entry was posted on Tuesday, December 16th, 2008 at 9:32 am and is filed under Studio construction. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.