240v through thermostat wire rated for 150v

[Majeztic]

I recently installed a rotary phase converter and three wall mounted switches around the shop. The switches are momentary start/stop push button type that were sold to me by the company I purchased the phase converter through. They recommended running 18/6 thermostat wire from the converter panel to the switches. I wired everything up per their instructions and all is working as expected.

Recently, for unrelated reasons, I took the cover off one of the switches to examine the light bulb and discovered it is rated for 220-240v. I probed the connection with a multimeter and, sure enough, there is 240v at the switch, however, the thermostat wire is only rated for 150v.

How concerned should I be?

 

[infinkc]

how long of run? wouldnt think its too many amps running through it, but kinda crazy they have that high of voltage going to the switch.

 

[Majeztic]

The longest run is probably about 50'. The bulb draws almost nothing in terms of amps (maybe 5ma). I'm not sure what amperage is drawn by the push buttons.

 

[mark-NJ]

Amps determines the copper size. Volts speaks to the dielectric of the insulation. While you might stay lucky for a long time, I would not personally run 240V through wire with a 150V insulation.

 

[N_Jay]

how long of run? wouldnt think its too many amps running through it, but kinda crazy they have that high of voltage going to the switch.

TWO POINTS THAT DON'T MATTER.

Length has to do with voltage drop, which is related to current and Guage, not insulation ratting.
Current has to do with guage and insulation temperature rating, not voltage ratings.

Given the margin in most specifications, you are probably ok, from a practical standpoint, but would worry about;
1) any moisture
2) insurance issues if you have a fire.

 

[BrandonV]

Sounds like they wanted you to use CL3 not CL2 if it was a power limited remote-control circuit.

 

[mike93lx]

Sounds like they wanted you to use CL3 not CL2 if it was a power limited application.

This. CL3 is rated for 300V

 

[mike93lx]

Thinking this over however... although CL3 is rated for 300V isn't the maximum for an AC class 3 circuit still 150V?

Perhaps this is considered a class 1 remote control application?

Way outside my wheelhouse, but this site says you are correct.

Classifying and Using Class 1, 2, and 3 Circuits

NEC requirements for remote-control, signaling, and power-limited circuits

www.ecmweb.com

The maximum circuit voltage is 150VAC or VDC for a Class 2 inherently limited power source and 100VAC or VDC for a Class 3 inherently limited power source. The maximum circuit voltage is 30VAC and 60VDC for a Class 2 power source limited by overcurrent protection, and 150VAC or VDC for a Class 3 power source limited by overcurrent protection.

 

[BrandonV]

Way outside my wheelhouse, but this site says you are correct.

Classifying and Using Class 1, 2, and 3 Circuits

NEC requirements for remote-control, signaling, and power-limited circuits

www.ecmweb.com

Yeah... IDK I'm sure some sparky will come in... but I feel like you need something rated for a class 1 remote control circuit (assuming this is what it is)... and that isn't thermostat wire...

 

[wyliesdiesels]

how long of run? wouldnt think its too many amps running through it, but kinda crazy they have that high of voltage going to the switch.

Length of run has no bearing on voltage rating of insulation

 

[RPH]

From the article cited.
“
Conductors of different circuits
Class 1 circuits can occupy the same cable, enclosure, or raceway without regard to whether the individual Class 1 circuits are AC or DC, provided all the Class 1 conductors are insulated for the maximum voltage of any conductor in the cable, enclosure, or raceway.”
So, no.