Where to add another circuit?

I added a circuit at my radio fuse when I wired up my Fog Lights. Now I am installing an Inverter and I need to add another circuit to power the switch for the relay. Where should I add this circuit?
Thanks in advance!
Bill

 

If you're just switching a relay, you could use the same circuit you used before. Relays take so little current to operate it won't matter.

That's assuming the actual power for the inverter is coming from another source (if it's large, probably directly from the battery).

 

Yes, as you said JKD, I am switching a relay on the #6AWG fused wire coming from the battery and going to a 800 watt Cobra inverter.
Would it be ok to splice into the other "Add a Circuit" that also switches a relay for the Fog Lights.

 

Electrically I see no problem. Those two relays together won't use a flea-watt.

The only thing I'd be sure of is whether the source is switched power or not. Do you want the amp running even if the truck isn't on?

 

The source for the switch is the Radio Fuse. The inverter and fog lights can't be on unless the key is on or on Acc.
Also both switches are lit when they are turned on and the Lights and Inverter are on. No lights in switches nothing is on.
Thanks.