can't find the fuse

I understand that all of these appliances are controlled on different circuts. I hought perhaps there might be some kind of "main" controling several circuts. I had been troubleshooting the over temp link in the ater heater ignition as sugested by bypassing it. the burner came on for an instant and shut down. since then, I have not been able to find current in those appliances.
Yes I did check the black box battery control box and there is no interuption on the gcfi circut. (but thanks for thinging of those possibilities I might have missed)