Two switches in parallel... will it work ??

[randyo]

you have a heat lamp... in a well house....

If I wired a 120v thermistat "120v switch" and a regular switch in parallel...would that work..

|nnnnnnnn switch nnn|
|nnnnn thermistat nnn|nnn|
................................ (lite)
hhhhhhhhhhhhhhhhhhhhhh|

IF the thermistat kicks, it the light is on
if I flip the switch, the light is on.
What happens if both are on at the same time????

Is there a code violaton with switches in parallel like this???

 

[Ed MacLaren]

Re: Two switches in parallel... will it work ??

The term "switch" can mean Control Device or Disconnecting Means.

Control devices are routinely connected in parallel where a load must be controlled by more than one actuating mechanism, as in your case.
A basic rule of control is -
On devices in parallel - Off devices in series.

There should be a single disconnecting means ahead of the control devices. I'm not sure of the NEC rule on this, but I'm sure someone will help with that.

Ed

 

[Len_B]

Re: Two switches in parallel... will it work ??

Paralleling the switches is fine, provided they are fed off the same circuit.

 

[jtb]

Re: Two switches in parallel... will it work ??

Although I would avoid this, I agree with Len.

 

[curt swartz]

Re: Two switches in parallel... will it work ??

Do the n's and h's represent the hots and neutrals? If so why are we switching the neutral?

 

[paul]

Re: Two switches in parallel... will it work ??

I see a violation if the switch that is used says 'off' when in the open position.

 

[luke warmwater]

Re: Two switches in parallel... will it work ??

Originally posted by randyo:

What happens if both are on at the same time????
The light will be on.

Is there a code violaton with switches in parallel like this???
Not that I could find. These type of circuts are commonly used in motor control, which I think Ed's post may have been based on.
I've seen and used this type of circut on various situations such as a timeclock and toggle switch to operate a contactor, or a photocell and toggle switch to operate a light fixture.
I believe Ed to be right about the disconnect if it was a motor control circut, 430.74.
If it were fixed electrical space-heating equipment, then 424.19. But under the scope of Article 424, IMO a heat lamp would not count(any other opinions on this?).
IMO you have a branch circut design that works.