On/off switch wiring to 1650 watt heating element

[DangersBrew]

I installed a Leviton 15/20 amp on/off switch into a plastic gang box hard wired into my hot rod cable. It’s a 1650 watt element and I wanted to safely turn the element off and on without unplugging from an outlet. My question is does the ground wires need to be connected into the on/off switch green ground nut or is it fine to not ground the wires to the electric switch since it’s in a plastic box. Can I just wire the ground wires together with a wire nut instead. As a precaution I ended up wiring the 2 green ground wires together with one wire nut and having an extra a long pigtail sticking out of the green twist then attached to the ground screw on the ground switch. I didn’t know if this was necessary or just having the ground wires that are wire twisted together with a twist wire connector is suffice. I attached a pic of the finished product.

 

[doug293cz]

Yes, the switch body (the green screw connection) should be connected to ground. The switch body is partially metal, so a potential shock hazard if it gets shorted to hot.

Brew on

 

[DangersBrew]

Awesome thanks! Glad I wired correctly the first time.

 

[Bobby_M]

while it's beneficial to make a connection to the ground screw I want to stress that it would be best to just strip some of the insulation off the ground wire and loop it around the screw rather than cut it. Having a solid connection to the immersion heater is the most important.

 

[doug293cz]

while it's beneficial to make a connection to the ground screw I want to stress that it would be best to just strip some of the insulation off the ground wire and loop it around the screw rather than cut it. Having a solid connection to the immersion heater is the most important.

Agree, that is the most reliable way to make the connection.

Brew on

 

[DangersBrew]

Thanks for the suggestion Bobby I went ahead and rewired it your suggestion and find it much easier and safe. Thanks

 

[bruce_the_loon]

Looking at the crimped part of the lugs, I would crimp a second time directly behind the current crimp position. Where the insulation flares slightly is usually where the metal tube of the lug begins and making sure the entire tube is crimped will ensure the best possible physical and electrical connection between the lug and the wire.

 

[Imhoppy]

As an alternate to a hard-wired on/off switch, consider using a router speed controller. The heating element can then be plugged into the device. The router power supply is plugged into a gfci outlet. I have used one like this and it works great for both on-off and especially variable control.

https://www.harborfreight.com/router-speed-control-43060.html

 

[DangersBrew]

Looking at the crimped part of the lugs, I would crimp a second time directly behind the current crimp position. Where the insulation flares slightly is usually where the metal tube of the lug begins and making sure the entire tube is crimped will ensure the best possible physical and electrical connection between the lug and the wire.

Thanks! I crimped it again.

 

[RufusBrewer]

As an alternate to a hard-wired on/off switch, consider using a router speed controller. The heating element can then be plugged into the device. The router power supply is plugged into a gfci outlet. I have used one like this and it works great for both on-off and especially variable control.

https://www.harborfreight.com/router-speed-control-43060.html

Hmmm.... Interesting device.

The spec sheet says 8 amp (~960 watts) capacity, the unit has printed on it 15 amp capacity. (~1,800 watts)

Is the knob a continuous rotation, as opposed to fixed steps? Does the unit get hot?

 

[Imhoppy]

Hmmm.... Interesting device.

The spec sheet says 8 amp (~960 watts) capacity, the unit has printed on it 15 amp capacity. (~1,800 watts)

Is the knob a continuous rotation, as opposed to fixed steps? Does the unit get hot?

Continuous rotation and it gets very hot. It does power a 1500 watt element when set to FULL or VAR and set on HI (max clockwise rotation on dial). Modulation works pretty good too. Hasn't burned up or failed, so far anyway. Been satisfied with performance. I bought it at Harbor Freight. The price was much cheaper there than other places.

 

[doug293cz]

Continuous rotation and it gets very hot. It does power a 1500 watt element when set to FULL or VAR and set on HI (max clockwise rotation on dial). Modulation works pretty good too. Hasn't burned up or failed, so far anyway. Been satisfied with performance. I bought it at Harbor Freight. The price was much cheaper there than other places.

The controller getting hot means you are losing a significant amount of your power in the controller, which means you are not getting your rated power out of your element, even at full power setting. If you don't need all the power the element is capable of, then this is not a big issue.

Brew on

 

[InspectorJon]

Hasn't burned up or failed, so far anyway.

 

[RufusBrewer]

Continuous rotation and it gets very hot. It does power a 1500 watt element when set to FULL or VAR and set on HI (max clockwise rotation on dial). Modulation works pretty good too. Hasn't burned up or failed, so far anyway. Been satisfied with performance. I bought it at Harbor Freight. The price was much cheaper there than other places.

Hot and solid state is a dicey combination. I do not know exactly what type of silicon device they are using in there. But if it is part of a something that sells For $17.99 retail, I know it is a pretty cheap hunk of silicon.

If (probably when) it fails, it will fail in one if two ways. It will pass zero voltage and zero current or it will pass full voltage and max current. Could ruin your brew day. What is your plan for either case?

I strongly advise that you start planning to replace it with something rated properly and up to the task. Until then, to extend it's life, do what you can to keep it cool and at minimum temperature. Ventilation, forced convection, mount it to something that hat can sink the heat.

 

[bruce_the_loon]

Hot and solid state is a dicey combination. I do not know exactly what type of silicon device they are using in there. But if it is part of a something that sells For $17.99 retail, I know it is a pretty cheap hunk of silicon.

If (probably when) it fails, it will fail in one if two ways. It will pass zero voltage and zero current or it will pass full voltage and max current. Could ruin your brew day. What is your plan for either case?

I strongly advise that you start planning to replace it with something rated properly and up to the task. Until then, to extend it's life, do what you can to keep it cool and at minimum temperature. Ventilation, forced convection, mount it to something that hat can sink the heat.

RufusBrewer is right, heat is a killer when it comes to these things.

Found a teardown modification of the unit, it has a 25A insulated triac using the back plate as a heatsink, so it is basically an incandescent light dimmer with an override switch. At least the triac is overrated for the 15A max of the unit. Nice page on Instructables about opening it up and replacing the back plate with a proper heatsink. Only thing I'd do differently would be to spray the heatsink with a nice high heat black exhaust spray paint to increase the radiative effect.

https://www.instructables.com/Harbor-Freight-Router-Speed-Control-Mod/

 

[RufusBrewer]

Looks like a good write up and good photos. For a project like this, you cannot have too much heatsink.

Consider replacing the triac. After some time of abusing it with excess heat, you might have created a walking wounded device and shorted it's lifespan.

It is a bit counter initiative, but painting the heatsink black is a good idea. I proposed that before on this forum and got push back. "Bad idea, paint is an insulator!" It is an old audio electronics. I have seen where heat sink manufacturers recommend painting a heatsink.