Do I need a SP or DP thermostat for a 240v bb heater?
What is the difference?
Thanks
Also any sugguestions on how to wire in a finished house would be helpful. I have access to the attic but not the basement ceiling so I am considering fishing 12/2 or 10/2 thru the interior walls or running pvc conduit on the outside of the house.
You need a DP stat. The setpoint will switch one of the 2 poles on and off, completing the 220v circuit, but dialing the stat down to off will switch off the other pole as well, effectively killing power on both hot legs.
For asthetic purposes, running conduit on a home's exterior would be my last resort.
SP means single pole, DP is double pole.
Back in the old days of power, they used to turn switches on and off wtih a big wood pole. A "double pole" is sorta old speak for two circuits that can turn on and off.
Single throw means one place you can connect the pole. Double throw is two different directions.
a double pole single throw thermostat allows you to turn both sides of the filament on and off -- much safer than leaving it always energized.
A single pole thermostat would be OK on a 110 volt system.
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