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Old 01-15-2012, 10:24 AM
Brimstone Brimstone is offline
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Figuring out relay amp ratings?

Hey All, I'm looking to do some custom wiring work with some of GM's later-model fuse/relay block and relays, and am having some difficulty finding any good specification-type documentation on the different relays that are used. I don't really have anything that would push these relays to their max, but it would be nice to know if it's safe to use one of the smaller relays in place of a larger one.

You can see what I'm working with in the pic below - the fuse block (with terminals removed) can be found in just about any later-model GM car (don't know what year they changed to this style terminal, but probably 95+) that almost exclusively uses Metri-Pack 280 style terminals for the relays and mini fuses, and Metri-Pack 800 terminals for the maxi fuses (the post on the right connects to a buss bar for the maxi's). The relays shown are the large & small SPST (grey) and SPDT (black) that would be used in this kind of fuse block and what I'm trying to find the amp ratings for.

Now, one way to guess at the ratings is to go with the max rating for the terminals, and the Metri-Pack 280 has a max amp rating of 30 amps with the correct wire (per Delphi's web site and terminal supply sites). So then my next question is do both the large and small relays have the same 30 amp rating or do the smaller relays have a lower rating?

I'd like to figure this out since being able to use the small relays would increase the number of relays that can be used in this fuse block - At minimum it can hold 3 large and 2 small relays, but at max it can hold 8 small relays giving quite a bit of flexibility in a custom situation.

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