Model 181 Kiln:  

       Power = 4400 Watts,  Voltage = 240 VAC 

       Current = P / V = 4400 / 240 = 18.33 Amperes.  

 Therefore on the basis of current ratings the standard 50 ampere switch will work. However there is one more thing to determine.  Next look at your kiln wiring diagram or your kiln directly.  See the example evaluation below regarding the usage in some older kilns of the neutral return wire.   

If you need help email your wiring diagram or make / model of kiln to: embeddedrf@cox.net

If your kiln gets close to this rating its advisable to go to a higher current rating switch.  We have this available at a nominal additional fee. 

Below is the diagram of a kiln that was converted over by a customer.

The switch included with the kit is rated at 50 Amps.  This kiln draws Current = 4400 Watts / 240 Volts = 18.33 Amps. This is far below the maximum 50 amps specified by the switch.  So on face value the switch should work.

However  there is a snag involve in using the standard one switch kit. Can you see it ?

 The problem is that this kiln uses one phase of 120 to run the lower ring of elements and the other phase to run the upper ring. 

   Black and White  run the upper ring.

   Red and White  run the lower ring.  

   ( where white is the neutral return wire )

 Originally the owner tried putting the single switch in the neutral return and the kiln would not shut off.  The reason for this is the current still would flow in the safety ground. 

The solution was to purchase an additional switch and put one in the red circuit and one in the black circuit.

The key here is to identify if your kiln uses the neutral return circuit or not.  If it does use it you'll need to switch BOTH hot wires on a 240 volt kiln.   An additional switch costs only 15$ so its not a big worry. 

If your kiln has a 4 prong plug it most likely uses the neutral return.  If it has a 3 prong plug it most likely does not and a single switch will do the job if your kiln draws less than 50 Amps. 

Most newer kilns do not use the neutral.