Control wiring for 24 150w HPS Street Lights

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I have two 30 amp circuits to feed 24 150w HPS street lights.

I have 1 2 pole, 240v, 30 amp contactor controlled by a photo eye.

Does the code allow me to feed one leg from each 30 amp feed to the line side of the contactor and the other leg from each circuit to the lights.

In other words use the contactor to break only one side of each circuit.

I say no, however I can't find justification in the code book.
 

don_resqcapt19

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Staff member
Location
Illinois
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retired electrician
Why not, it fits the description in Art 100 for a MW branch circuit doesn't it?

dick
Because 210.4(B) requires that the means of simultaneous disconnect be at the point where the branch circuit originates. The branch circuit does not originate at the contactor.
 

don_resqcapt19

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Location
Illinois
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retired electrician
Irrespective of what Code says, you should break both hots, particularly on street lighting whereby someone might assume that because the lights are off, the power is off too.
In this case the code does require that the contactor break all of the ungrounded conductors,(see 410.104(B)) but that is not required for many other applications. You can never assume the power is off no matter what. You always have to verify.
 

dbuckley

Senior Member
You can never assume the power is off no matter what. You always have to verify.
Preaching to the choir, but not everyone sees it that way.

One could argue it served the janitor right that he came off his ladder 'cos he got shocked touching a live circuit he thought was dead when he was changing the bulb, but that's not an argument I'm happy with. "Apparently off" should mean "really off", especially when its its a just a few bucks difference to do the job as well as it can be.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
What is the voltage of the fixture? 120v or 240v?
240v 2pole what is the coil voltage? 240v rated contacts like 300v/600v rated?
2 30a hr are they 240v hr or 120v hr?
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Its not a MWBC as it does not meet the definition (no neutral). Even if a two pole contactor, that should not be depended on for a disconnect, thats at the CB.
Also I have designed a lot of roadway lighting, we put fuse holders in the base of each pole and run 12 AWG Pole and Bracket cable up the pole.
 
410.104 Electric-Discharge Lamp Auxiliary Equipment

410.104 Electric-Discharge Lamp Auxiliary Equipment

Is the "Auxiliary Equipment" that is referred to here mean the ballast, igniter, and capacitor? I can't find any other referrence to this.
 

RichB

Senior Member
Location
Tacoma, Wa
Occupation
Electrician/Electrical Inspector
What we do in Wash DOT is bring both hots (240 or 480VAC) to the contactor from the CB then out to the lighting. We use a 120VAC circuit to power one photo cell mounted on the service/control cabinet that runs the contactor. That way both hots are broken when the contactor or breaker is off. On 120VAC loads we do it the same way except we only break the hot not the neutral. On MWBC (as in City of Seattle) we pull a full boat and break both hots on one contactor and use a standard 2 pole breaker. Works great and always ensures circuits are dead.
 

Electric-Light

Senior Member
I didn't realize street lights use 240v. I thought they'd use 277 or 480.

If it's 277 (L-N), then one pole is fine, but if its 480 (L-L) then I think both poles need to be switched.
 
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