Electrical Guru’s I need help.

[87bob]

I have four high bay lights. I know from experience that if I try to run all four on the same (20 amp) breaker I pop a breaker. I have been running two on one 20 amp circuit and two on another. I have to recheck the amp draw. Here is my question. I want to flip one switch to turn on all four. Can I use a single throw double pole switch and operate two on one pole and two on the other? As I recall they draw approximately 7.5 each. In the panel I use would a double 20 amp breaker and 12 gauge wiring to cover each circuit. Am I correct in my thoughts? Thanks in advance for your input.

 

[wyliesdiesels]

How about a lighting contactor? Switch operates the coil in the contactor which then provides power from a separate higher amp circuit to power the lights.

Or switch to LEDs

 

[Terry D]

A lighting contractor will work, they can be costly. The double pole switch would work also. You are with in your limits on a continuous load, 80% 0f the circuit rating. Switching to LEDs would be your best bet and save you money in the long run. Also if you would use a double pole switch, the 2 circuits should be on a 2-pole breaker

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[Bert_]

What are the lights?

 

[AntonLargiader]

I had the exact same problem with four 400W LPS lights in my previous shop. I rewired them for 208 (what the building had) and the problem was solved, since the current was nearly halved.

 

[Bert_]

I had the exact same problem with four 400W LPS lights in my previous shop. I rewired them for 208 (what the building had) and the problem was solved, since the current was nearly halved.

I seriously doubt you had LPS (low pressure sodium) lights. Not to mention LPS doesn't come in 400w. LPS is used for street lighting but even for that it it far out numbered by HPS (high pressure sodium).

You probably had metal halide.

 

[AntonLargiader]

You're totally right. Brain fart. They were metal halide.

 

[Norcal]

I seriously doubt you had LPS (low pressure sodium) lights. Not to mention LPS doesn't come in 400w. LPS is used for street lighting but even for that it it far out numbered by HPS (high pressure sodium).

You probably had metal halide.

Agreed, the largest LPS lamp is 180 watt & fairly long (4'?) + the monochromatic yellow color is worse then the amber color of HPS indoors.

 

[TRWham]

I seriously doubt you had LPS (low pressure sodium) lights. Not to mention LPS doesn't come in 400w. LPS is used for street lighting but even for that it it far out numbered by HPS (high pressure sodium).

You probably had metal halide.

Back in the early 80s, Georgia Power tried LPS for interior lighting in their new 333 Piedmont building in Atlanta. I worked there as a co-op when the building was just completed. It took a little getting used to, but it worked okay. The color was obviously one difference, but there also seemed to be less reflection off of surfaces, so everything seemed very matte. I understand they eventually retrofitted some other system, but I have not been back in that building for many years.

 

[87bob]

A lighting contractor will work, they can be costly. The double pole switch would work also. You are with in your limits on a continuous load, 80% 0f the circuit rating. Switching to LEDs would be your best bet and save you money in the long run. Also if you would use a double pole switch, the 2 circuits should be on a 2-pole breaker

Sent from my SM-G960U using The Garage Journal mobile app

When you say a two pole breaker are you referring to one where the two legs are tied together or both legs are in the same breaker? Thanks all for the advice.

 

[Terry D]

When you say a two pole breaker are you referring to one where the two legs are tied together or both legs are in the same breaker? Thanks all for the advice.

Either one, either a 2-pole breaker or 2 single poles with a tie handle. It has nothing to do with if one circuit trips, the other will also shut down. It has to do with if you have to shut one circuit down for what ever reason ( repair, maintenance ) it will also shut the other down. It is a disconnecting means for safety. If two circuits share the same device, both must be able to be turned off simultaneously.

 

[AntonLargiader]

Back in the early 80s, Georgia Power tried LPS for interior lighting in their new 333 Piedmont building in Atlanta.

I can't imagine having such a monochromatic light in a working area. Lighting with poor CRI really affects me; not just the color rendering itself but the clarity and definition of everything seems to suffer.

 

[Bert_]

I can't imagine having such a monochromatic light in a working area. Lighting with poor CRI really affects me; not just the color rendering itself but the clarity and definition of everything seems to suffer.

Yup, I think LPS has a CRI right around 0

 

[tfi racing]

Do yourself a favour and get rid of those energy hogging **** lights, not worth the effort of dicking around with a contactor.

 

[Bert_]

Do yourself a favour and get rid of those energy hogging **** lights, not worth the effort of dicking around with a contactor.

We don't even know what the op's lights are...

 

[u2slow]

If the lamps are getting old, you may only be getting half the light output.

If you refit the fixtures with the popular LED 'corn' lamps (gut/bypass the ballast) you can probably run all four on the same circuit - no rewiring.

 

[AntonLargiader]

He'd probably need 300W bulbs ($200+ each) to replace the light of the 400W MH lamps that we assume he has. And those MH could have better light quality.

Metal halide is roughly the efficiency of fluorescent, when new or close to it. And they can be pretty high CRI depending on the bulb. The only thing I didn't like about mine was the noise; it was more of a ringing than just a hum. I was SO happy to eliminate that.

 

[u2slow]

He'd probably need 300W bulbs ($200+ each) to replace the light of the 400W MH lamps that we assume he has. And those MH could have better light quality.

My brother just redid a bunch in his shop this past month with amazon stuff.... 250W corns ($145 CDN) and complete 250W LED fixtures ($170 CDN) put out similar light. Roughly on par, if not more light, than when the 400w MH's were new.

Will have to take note of how long they last....

EDIT: Yes, the noise. The lack thereof was noteworthy.