Lighting Contactors

[electrofelon]

Using a DP contactor is inherently an NEC 110.3(B) violation. It is not listed, so you cannot use it as intended in its listing. Take that for what its worth to you.

DP should stand for “Don’t Purchase”.

I am not aware of any requirement for them to be listed so what is the problem?

 

[jim dungar]

Definite purpose means they're for a particular application

Which means each application of a DP needs to be evaluated.
For the most part the amp rating of a DP contactor is based on resistance heating as found in HVAC applications. These often need to be severely derated when used as a motor starter or a lighting contactor.

I stopped pushing DP contactor in favor of IEC style contactors 40 years ago.

 

[electrofelon]

I have used them frequently and not had any problems. I do usually use them at the top of their rating.

 

[jim dungar]

I have used them frequently and not had any problems. I do usually use them at the top of their rating.

Which rating? How often do they cycles?
The last DP application charts I saw had different amp ratings for resistant heating, tungsten lighting, balasted lighting, motors, and capacitors. Their contact material and size is so 'cheap' different loads impact the the make and break and duty ratings.

 

[Strathead]

I’ve used DP contactors for about anything imaginable because I’ve seen them used that way by mfgs.

Hadn’t thought of IEC but they are more commonly available than in the past.

The advantage of the lighting contactor is they latch in, and the ones I’ve dealt with, can be manually transitioned when a coil fails.

Just FYI lighting contactors as a whole don't latch in. You must specify electrically held or mechanically held when asking for a lighting contactor to properly specify or order a contactor. They make both.

 

[electrofelon]

Which rating? How often do they cycles?
The last DP application charts I saw had different amp ratings for resistant heating, tungsten lighting, balasted lighting, motors, and capacitors. Their contact material and size is so 'cheap' different loads impact the the make and break and duty ratings.

I don't have any specific numbers I can provide off the top of my head. Many of the labs I set up have things like fans and blower's that need to come in with the lights, or additional fans that need to come on with the fan in a factory hood assembly. Lots of stuff like that.