Timed disconnect suggestions

M

marmathsen

Senior Member
Location
Seattle, Washington ...ish
Occupation
Electrical Contractor
I have a project coming up where I need to wire for an outdoor residential 9kW sauna. In the installation instructions they state:
When this heater is not installed for use with an attendant, a timed-cutoff switch must be connected in the input circuit to disconnect all ungrounded conductors of the heater circuit from the supply source at the end of 1-hour of operation. The timed-cut-out switch shall be located outside the heater room, or mounted to a wall or door inside the heater room. The time feature of
the switch must not lend itself to being overridden.
Click to expand...
I haven't talked to the manufacturer but does anyone have a suggestion on what I might use here? The unit has a separate 24v keypad for turning the heater and lights on and off. Is there something that could be wired in either AS the disconnect or adjacent to it that would automatically start a 60 min timer after the heater turns on that could disconnect power and reconnect it after some period of time?

Also, I wonder what they mean by "attendant"

Rob G
Seattle
 
A rated contractor for the correct amperage and voltage. With 24v coil. And you could also use a timer a digital timer switch to pull in the coil as well.
 
Cursitti said:
A rated contractor for the correct amperage and voltage. With 24v coil. And you could also use a timer a digital timer switch to pull in the coil as well.
Click to expand...

And perhaps some sort of current sensor that triggers the timer?

I assume I could piece together an expensive, complicated setup.

I'm wondering if this is a more common setup in other areas of our industry. Is there some all in one product? Or does everyone just build their own with individual components (current sensor, contactor, timer, some sort of logic controller, all in a pretty little box)?

Rob G
Seattle
 
Probably to prevent hypothermia. Though I thought it should shut off the jets too. The one I had many years ago had that timer built in, though it could be reset, but not permanently.
 
ptonsparky said:
Well I could set up a small PLC, an HMI with Wi-Fi connection, but a simple one-hour spring wound timer controlling a contactor should work. Don't get the timer with the hold feature.
Click to expand...
I thought about that too. The disconnect is on the house before the circuit dives into the ground over to the free standing sauna. The 24v controller is mounted on the side of the sauna itself. I suppose I could put the timer on the side of the sauna next to the controller downstream of the disconnect. I guess I was hoping for some sort of automated setup so no one needs to touch the timer, it starts automatically and ends kills power after an hour automatically.

Rob G
Seattle
 
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