Light switch on 4500w element failed

[smashed4]

I have a very simple setup for my HLT :

20 amps, 12 awg circuit with 20 amps GFCI breaker
4500w water heater element installed in kettle
In-line DPST "light switch" like this one :

2 Pole Switch 20 Amp 120/277v
https://www.homedepot.ca/en/home/p.2-pole-switch-20-amp--120277v--white.1000159440.html

So instead of a fancy PID, I just turn it ON to start heating the water and OFF when I reach strike temp. Simple as that.

The switch has been used for about 20 hours in its lifetime.. did maybe a dozen batches with it in about a year.

Last brew session, the switch failed!

I thought it was the heating element that failed but I tested the circuit with a voltmeter and I have 246v coming in the switch, and only about 30v coming out of the switch in ON position.

I have a second, identical circuit with the same switch model and I have 246v going in and 246v going out. This circuit is used with a 3500v induction plate for the brew kettle and it works fine.

I did notice once that the light switch was slightly warm when the electric element was on, but nothing extreme so I did not put too much attention on it..

I inspected the wiring and the connection on the switch and it is solid and tight and there is no visible heat marks or loose connections..


Is it normal for a light switch to fail so early?

Should I replace it with a higher rated switch? There seems to be 30 amps switches in the same form factor available.. but the circuit and breaker are 20 amps and they never tripped.. why would a 20 amps switch fail so fast ??

Did I just get a bad switch ??


Thanks!

 

[ITV]

Your pushing 19 amps on a 20 amp switch without taking into account inrush current, I would go with a 30 amp switch.

 

[SleepyCreekBrews]

Your pushing 19 amps on a 20 amp switch without taking into account inrush current, I would go with a 30 amp switch.

I'm pretty sure there's no "inrush" current on a strictly resistive load .

Having said that, It would be an excellent idea to pick a switch with a little more safety margin this time around

 

[BowAholic]

Leviton
Model # R62-03032-2WS
Store SKU # 589535
30 Amp Industrial Double Pole Switch at Home Depot for only $11.48

 

[smashed4]

Seems unanimous, I Will replace with 30amps switch...

Unfortunately they are not that readily available up there in canada.. Amazon.ca seems to have one for 35$ .. Ughh

 

[stevehaun]

Buy a double pole contactor for less than $15 and a cheap switch for less than $5. Safer and cheaper.

 

[Jaybird]

I personally would be using a relay. That is a fairly large current pull to arc a simple switch with, even if rated for 20 you were killing it with full load. A 30 amp switch will last longer for sure but being a full current resistive load its the arc flash that kills the switch. Relays have a MUCH higher tolerance to arc flash. They are build for it. Then your not "handling" 240 VAC. I was never a fan of a 240 VAC switch. 18 years as an industrial electrician I always added a relay not just for longevity but safety.

Cheers
Jay