Wiring up two high amp draw items on a transfer switch

beniwen

I am having a bit of a problem coming up with a solution to a wiring predicament.  

I want to have two high amp items wired into the same inverter.  But, I only want to be able to use one at a time.  
Now I could just make sure that I don't use them at the same time.  But, I want a failsafe that makes it so that one item has priority over the other if they are both turned on.  

I will have an induction cook top (1800watts) and a electric water heater (1500watts) hooked up to a 3000watt inverter.

I would like to give the induction cook top priority over the water heater whenever they are both turned on.   
I need all of this to happen automatically.  

Is there some type of relay or transfer switch that could make this possible.  

Thanks for all the help and comments!

BB.

Welcome to the forum beniwen,

Does something like this work for you?

Search for "Current Sensing Relay" (Amazon seems to be a good, low cost place to start):

https://www.amazon.com/CrocSee-Miniature-Normally-Monitoring-Detectable/dp/B086YT49H7

Connect one of the power lines through the current core to the Induction Plate--When it turns on (over a few amps), then it closes a contact--That can control a digital or mechanical relay and cut the power to the water heater...

That would be pretty simple--The current sensing relay is not cheap--$20--But is much less than some other industrial rated units I have found ($50-hundreds of dollars).

You could look at the water heater--If it has a low voltage temperature controller--You can use a much lower current rated relay to cut power... If there is no (easy to access) low current control circuit--Then you would need a higher current rated mechanical or digital relay.

You would need to match the current sense output voltage to the input of the heater relay...

I think this does what you want... Is it possible that you can "build your own" current sense relay (few turns of 120 VAC wiring and fewer turns of sense wiring that could control the heater relay).... You have to be careful with current sense "transformers" because their output voltage can be hundreds or thousands of volts if they are not connected to a (typically resistive) load.

As with anything dealing with line voltage and larger current--You will have to be careful and know what you are doing. Don't what you to hurt yourself or start a fire.

-Bill