Question about relays

scruffythewild

New Member
Jun 10, 2012
464
Nassau County, New York.
Hello,

Having a hard time finding this on any forum. What gauge wire can be used as the trigger wire for a relay. The relay is powering my Hella lights which in total is 110W. I just want to know what I should fuse the low power wire running from the switch box to the relay at. Also how big should that "Low Power" wire be?

Thanks!
 

shues

Lifetime VIP Donor
May 21, 2010
10,276
NW Indiana
Please understand that the wattage of the load passing through the normally-open and common contacts of your relay has no bearing on the gauge of the wire required for the relay coil, or the size of the fuse you should use to protect the wire.

The best way to determine the load presented by the relay coil is to use an ammeter in line with the relay coil. Unless the relay you are using is grossly oversized, I anticipate the load presented by the relay coil will be quite small. It should be well less than one amp.
 

scruffythewild

New Member
Jun 10, 2012
464
Nassau County, New York.
Thank you!!


Please understand that the wattage of the load passing through the normally-open and common contacts of your relay has no bearing on the gauge of the wire required for the relay coil, or the size of the fuse you should use to protect the wire.

The best way to determine the load presented by the relay coil is to use an ammeter in line with the relay coil. Unless the relay you are using is grossly oversized, I anticipate the load presented by the relay coil will be quite small. It should be well less than one amp.


http://www.rattlebars.com/avalanche/relay_basics.html

usually its milliamps needed to activate a relay... 18 - 20 ga should be fine
 

JazzDad

Member
Aug 5, 2011
5,165
USA
The missing factor in the equation is the length of the wire.
 

Jarred J.

Lifetime VIP Donor
May 21, 2010
11,580
Shelbyville, TN
but thats only TO the relay... the relay can be 2 inches from the switch...
 
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