- Joined
- Dec 8, 2013
- Messages
- 2,651
When working with 240V it is my preference to switch both sides of the line. That way the load, in this case the heating element, is completely de-energized, rather than still being electrically hot relative to ground. It would take 2 solid state relays to create a double pole relay to do the same thing. Also with a SSR there is always some leakage current, not much, but they really never turn off 100% thus could be a safety hazard under some conditions. An electro-mechanical relay is better in this regard, not 100% fool proof, but better.
I always want a seperate two-pole mechanical switch or contactor upstream of and independent of the controller. Given that I have no problem with the controller switching only one line.