Please advise on wiring a current sensing relay with a wall timer. Safety is #1!

[BKG420]

Hello,

I am currently running a light controller identical to this one except I have an in-wall digital timer controlling the main 30A relay:

https://www.icmag.com/ic/showthread.php?t=301017


I am anal and want to take safety to the next level. I want to add a current sensing relay with time delay in order to shut off my light in the event my fan stops working. It will also add a time delay in the event of power outages to prevent hot re-strikes since my ballast lacks that feature.

I have this CS relay: http://magnecraft.thomasnet.com/item/all-categories/820/pn-2927

According to what I have read, when talking about relays, the "common (c)" connection is not a neutral wire, but a hot wire. Going off that, I plan to wire to switched load output of the wall timer to the "common" (c)" on the CS relay, then from there to the control wire of the main 30A relay.

The idea is that under normal operation, the CS relay will sense current from the fan being on, and will be in a closed circuit state, passing the wall timer's switched load to the main 30A relay. This way the wall timer is what will control the lights turning on and off.

In the event of a fan failure, the CS relay will no longer sense current and flip it self into a open circuit, cutting off the signal from the wall timer, and turning off the lights. Then no matter what the wall timer is doing, the CS relay will be blocking the signal from it, keeping the lights OFF.

In the event of a power failure during normal, the CS relay will sense current again from the fan, but instead will delay flipping to a closed circuit, preventing a hot re-strike.

Does that sound right? ANY help or advice is greatly appreciated. Thanks!

 

[Bababooie]

Overkill my man. Since you have a contactor for the lights, just put a thermostat in the control circuit to kill the contactor if the heat rises from a fan failure. Simple and cheap.

 

[BKG420]

Overkill my man. Since you have a contactor for the lights, just put a thermostat in the control circuit to kill the contactor if the heat rises from a fan failure. Simple and cheap.

I agree, it is overkill. But then again my whole setup is overkillconsidering I only run a 250w HPS off this rig when its built to handle over 20A.

The thermostat is a great idea, but since I already had the relay from a previous project and wanted a time delay integrated, the CS relay was the way to go for me.

Thanks!

 

[Avenger]

Not quite right.
The 820 series is only a timer function relay, the 841 series is the current sensing relays.

here is the wiring schematic for the 841 CS relay:

The x with the circle aroud it is the load which current you are monitoring, in your case that means the fan.
A1 is the 120 volt hot wire from the main fan power, B1 is this same hot line coming out of the current sensor going to the fan.
A2 is the common grounded leg of the 120 volt main fan power.

15 & 18 are the normally open switch contacts

 

[BKG420]

Doh! Well shoot, I thouht I had the right one. Unfortunately the 841 series only had a max of 10 second delay, so that wont work for hot re-strikes. The 821 can do up to 10 days!

I may just buy the one from CAP which is a 15 min delay as well as temp sensor and take the thing apart, or build my own. Thanks!