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AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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My name is ***** ***** and I was called by a car body shop

Customer Question

Customer: hi my name is ***** ***** and I was called by a car body shop to finish a fire suppression system installation started by other, I have a universal control head with 6 wires coming out of the box and I was asked to wire this control head in a way that a siren and strobe light will be activated when needed and power to the fan in the paint booth would be shut off. I have never installed a system like this before and was hoping to benefit from an experienced electrician.
JA: Thanks. Can you give me any more details about your issue?
Customer: Ok when I approach the site, the customer showed me a badger chemical system with sprinkler heads already in place. He showed me where thet have fastened the B120099 universal control head attached to absolutely nothing. and a switch across the way that turns the fan in the paint booth on/off. He showed me a strobe light in a box and told me that he needed help because he is having a fire inspector next month and he needed the system properly installed. Since I have never done it I thought it would be a good experience. The fan is 120V Although the shop is 3 phase. he mentioned needing a shunt
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Submitted: 1 year ago.
Category: Electrical
Expert:  AssuredElectrical replied 1 year ago.

Welcome. My name is ***** ***** would be glad to assist.

Can you first, check the wires and find the 3 wires that go to each of the micro switches?

Should be one common, one NO and one NC to each of the switches.

Also, verify the actual motor for the fan is 120 volts, as with 3 phase supply, the motor is most likely 3 phase to be large enough for air changeover.

Let me know and we can continue,


Customer: replied 1 year ago.
Will text you when I am in front of the UCH. I remember there were 2 sets of wires each blue yellow and brown, the only difference was a white stripe on one set. These wires were just hanging out of the UCH. I will check the fan to verify phases, as I am relating what I was told by shop owner.
Expert:  AssuredElectrical replied 1 year ago.

Ok, very good.

There should be 2 micro switches with 3 wires each.

One switch would control the alarm strobe and siren, the other the fan shutdown.

If the fan is 3 phase, you would need a contactor or a shunt trip breaker for it.

The strobe and siren are the easiest, as they can wire directly to the micro switch

Will await your post


Customer: replied 1 year ago.
Ok you were correct, I went to the old plate on the motor and is 3 phase. 120/208/120
Customer: replied 1 year ago.
in order for me to use the micro switches provided in the UCH what do I have to do.
Expert:  AssuredElectrical replied 1 year ago.

First we need to test and find out which wire on each one is COM, NO and NC

Then a diagram can be made for the situation.

Customer: replied 1 year ago.
Ok the blue wire is common, the yellow is normally closed and the brown is open
Customer: replied 1 year ago.
I had continuity between the blue and brown
Expert:  AssuredElectrical replied 1 year ago.


If you had continuity between blue and brown, then brown is closed not open.

Need to know which it is please.

Customer: replied 1 year ago.
I have continuity on the brown and blue but the diagram states the brown should be open. Sorry sent you info based on diagram and then tested.
Expert:  AssuredElectrical replied 1 year ago.

If I assume the brown is normally closed and yellow normally open, it will wire as seen below

Not sure why they state one thing and it is different?

Customer: replied 1 year ago.
The only thing we can think is that the diagram may be correct once the system is engaged?
Expert:  AssuredElectrical replied 1 year ago.

That is probably the case, so you would swap the yellow connection to the brown.

if you could power to check, you could be certain.

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