3 controllers burned up when turned on! Help!!!!!

[Guest guest]

lonewolvie wrote:

Just a thought, I would try replacing the transformers. The rest of the board shouldn't be affected, the triacs and opto-isolators are rated for 220 VAC use.

Just don't let the same guy who did the breaker wiring for you wield the soldering iron...

[Guest guest]

Scott..did you ever get back up and running?

[schristi69]

So your staff tried to save a few buck using one length of 3 conductor for both circuits instead of 2 conductor for each circuit ? I was always taught to keep it simple and your circuits separate. Getting fancy gets you electrocuted.

[KarlSmith]

Doesn't the white need to be thicker to handle 2 circuits at once? If I remember the rules correctly 10 ga. for 30 amps.

[-klb-]

I'm wondering if this was on 3 phase 4 wire delta, with a stinger phase or some such. On single phase, and sharing the neutral, you want adjacent breaker spaces, so that current in your black and red will subtract from each other in the neutral. I'm trying to figure out exactly what, besides a failed neutral connection will give the 180V result.

But agreed, new wiring is always good to check out with a meter before plugging hardware into it.

[James Shelby]

Looks like they shared the neutral then it came loose I have seen this many many times. I break the right hand tab off the outlet and feed it with 220v all the time, it will give you 20amps 110v on the top plug and a second 20 amps 110v on the bottom plug but (the big but is) if the neutral ever comes loose it will smoke the controller every time. That is part of the reason I took the second power cord out of all my controllers.

[KarlSmith]

-klb- wrote

On single phase, and sharing the neutral, you want adjacent breaker spaces, so that current in your black and red will subtract from each other in the neutral.

Never put that together in my head. Makes perfect sense.

[DanglinModifiers]

This sounds eerily familiar....

[Max-Paul]

Karl,
Just to put a different twist on the answer.
Ok, Neutral wire comes loose and is no longer conducting. Remember ohms law and Kirchoff's law. This means that if the resistance (yes its impedence in AC) on one plug is say 120 ohms and the other plug has 60 ohms on it. 2/3 of 220 will be on the first plug and 1/3 of 220 V will be on the second plug. Lets give that some numbers. so 2/3 of 220 is 146 volts and 1/3 of 220 is 73 volts. So, this can get worse depending on the resistance load ratio between the two plugs. Then too, if your really good and got a balanced load between the two load, then the voltage would be shared equally. But with all of the lights blinking, what are the chances of that?

[KarlSmith]

In my house the only place I installed 3 wire with a shared neutral is for a ceiling fan-light combo. Where both can be on 2 wire but I split them for separate control at the wall.