How did I wire this incorrectly?

[dhumac]

Also known as - how did I screw up!

I don't have a picture, but here is the layout. I'm wiring a 5000 watt garage heater - 10/2 wire to the heater (30 amp double pole).

Wiring to the heater:
Black load to black heater wire and white load to red heater wire.

Wiring to the thermostat:
I have a 28 amp double pole thermostat. I wired black to black and red to white. Now the problem is I didn't have my reading glasses and I'm not sure if I wired the load to line side or load to load side - I actually looked for something that indicated line/load on the thermostat, but I could see it.

When I switched to power on it was fine, but then when I turned the thermostat on, it sparked at the thermostat red wire and tripped the breaker. I then turned the power off and unwired the thermostat and capped the wires until I can figure it out.

So - if I wired load side to line side I wouldn't have expected it to short - but I could be wrong ... am I? Or could it be something different? Any pointers or direction would be appreciated. I've never wired a double pole thermostat before - single pole ones yes.

Thanks for any pointers.

 

[ddawg16]

Red wire? Where did the red wire come from?

 

[dhumac]

My 10/2 was black/white the thermostat was black/red+black/red and the heater is black/red.

I kept all black together, and paired red to white all along.

 

[The Cobbler]

I'm thinking the white is neutral not load

 

[dhumac]

This is 240v - no neutral, its hot/hot.

 

[The Cobbler]

sorry, misread your post. sounds like you wired the stat wrong and shorted when you turned it to call for heat

 

[zmaxmotorsports]

Pictures,where did you find a 28a 2p breaker?

 

[dhumac]

Yes, standard 240v/30amp breaker - black to one of the breakers, white to the other (wrap it with electrical black tape for the inspector to sign off on) - ground to ground bar.

The thermostat is 28a.

 

[Bert_]

Did you look at the the instructions for the stat? Many times the black wires are line and load is red.

 

[wyliesdiesels]

Post some pics

 

[bigb56]

Did you look at the the instructions for the stat? Many times the black wires are line and load is red.

yep. I learned that lesson after frying my first base board heater stat.

 

[dogdog]

..... I think that thermostat is suppose to break one of the power legs... ONLY
so if you have 240V... chose the black to black or the white to red to connect your thermostat.. NOT both.

 

[Bert_]

..... I think that thermostat is suppose to break one of the power legs... ONLY
so if you have 240V... chose the black to black or the white to red to connect your thermostat.. NOT both.

Very possibly if this is a single pole stat, I got the jest this is a double pole but could be wrong. Again read the instructions.

 

[dhumac]

Got my electrician buddy to drop down ... I needed all red to one side all black to the other ... the back of the thermostat was ambiguous. It had load labeled to one side with both red and black wires coming from that side of the thermostat, and line then also had red and black wires. I needed to tie the Reds to the white and black from the panel and then the blacks to white and black to the heater.

It’s now toasty in the workshop. Just gotta finish the garage itself and life will be good ... we’ll warm at least.

 

[wyliesdiesels]

so you had a line to line short?

This is why pictures wouldve been very helpful. Hard to diagnose something like this over the internet without seeing it...

 

[6PTsocket]

This is why nobody should be without at least a cheap multimeter. A quick continuity check and turning the stat up and down enough to get the contacts to open and close would have showed you what was going on. Even a simple battery powered trouble light would have been good enough for this job. You obviously understand how it should work so it would have been a piece of cake to check out what that stat was doing.

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[teamextreme]

And this is why manufacturers need to do a better job of labeling terminals. I've ran into instances like this before myself, with no markings to indicate what wire is what. Agreed, that's when you pull out the meter, but you shouldn't have to.

 

[6PTsocket]

And this is why manufacturers need to do a better job of labeling terminals. I've ran into instances like this before myself, with no markings to indicate what wire is what. Agreed, that's when you pull out the meter, but you shouldn't have to.

After you have figured out how it should work, the marks make perfect sense. Sometimes not so much, before. What shoud be and what is are not the same thing. You have to deal with what ya got.

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