Question about relays

[adamforsythe]

Lets say you have a HUGE light or fuel pump or something like that and it draws 20 or even 25 amps. Lets say you have a 30amp relay in...is this good or bad? Should you match up the relay with the light amp or is it ok to have a bigger amp rated relay? I would think it would be better to have them match up.
Thanks
Adam

 

[loafer]

The relay can be larger than the load you are switching. I'm using a 30A to switch my 10A fuel pump becsause that's what I had.

 

[Greg72]

The relay needs to be rated at least as high as the item you are switching....more is fine.

Fuses are a different story, you don't want to use an excessively high rated fuse to protect a circuit since you'll probably damage the wiring before it blows.

 

[longbedder]

You WANT the relay to be rated larger than the load going through it. A 30A relay on a 20A load is good.

 

[adamforsythe]

sweet thanks guys

 

[vortec]

The relay needs to be rated at least as high as the item you are switching....more is fine.

Fuses are a different story, you don't want to use an excessively high rated fuse to protect a circuit since you'll probably damage the wiring before it blows.

i realize you already have your answers, but i'll back them up. this is exactly right. i'd rather run a 10amp fuse on a 20 amp circuit and blow the fuse than run a 30 amp fuse and toast the wires.

one of the relays i use on a 20 amp circuit is rated 60amps