Best way to wire up a Hobbs Switch

[49-blues]

Like the title says-is there a best way of wiring in a Hobbs switch for a double pumper fuel pump.

 

[cdsttype]

On mine i used the hobbs switch to complete the ground for the second relay.
On the primary side of the relay.

 

[49-blues]

Thank you for that-it's a consideration I hadn't thought about, I thought I would put it on the hot side but breaking the groung might be better.