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Contactors, 208v, 240v lighting questions. #217250 06/10/16 06:50 PM
Joined: Aug 2005
Posts: 248
T
Trick440 Offline OP
Member
Hey guys. I just went to troubleshoot a large grow room. Breakers are tripping for the 36 - 1000w HPS lighting. The building is 208v, the lighting is 240v.

I unplugged all the ballasts and fired up the breakers and contactors. Everything held and no tripping breaker. I tested voltage at contactors and receptacles, everything is 'OK'. I told the guy looks like hes got some bad ballasts.

I started plugging in 1 ballast at a time to try and find the bad ballast. Well come to find out every ballast is bad. Most are just not working, a few others pop'd, sparked and smoked. After the 2nd pop, spark and smoke I stopped.

Scratched my head for a few minutes.

Went back to test the contactors. I killed power to the coil and tested the contactors in the normally off position. There was voltage on the load side while the contactor was off!

I'm thinking the contactor failed and when it shut off it didn't shut off fully and must of sent 208v down a leg and fried the ballasts. Quite odd it happened to all 4 contactors.

Hes running these same contactors and same load in another room and its been fine for 6 months.

The stats on the contactor are: FL=40a, RES=50a. The load was 9000w of HPS lighting powered by an electronic ballast.

I told him his contactors are overloaded and basically welded together, creating 208v down 1 leg and destroying his 36 ballasts. $10,000 in damages. He had a hard time believing it, saying the contactors are rated for 50a and they shouldn't do that. I told him they should be rated atleast 20% higher... I was talking outta my ass at this point cause I really don't know. smile

Can you guys give your opinion on this and tell me the proper sizing for the contactors. Or maybe he needs a different type of contactor, idk. My contactor experience is little.

Last edited by Trick440; 06/10/16 06:52 PM.

Shake n Bake
Work Gear for Electricians and the Trades
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217251 06/10/16 09:50 PM
Joined: Apr 2002
Posts: 7,178
HotLine1 Offline
Member
Trick:
It was a tough day today for me, but....

You said bldg. is '208' and lighting is '240'; is there any buck-boost transformers in the circuit?? Or are the ballasts on the 208 taps??

Get the info off of a ballast regarding 'operating' and 'start-up' amps, then check your ratings.

Did you clamp the loads on the contactors in the 'other room'??

How do you figure "208v down 1 leg"??

Last edited by HotLine1; 06/10/16 09:55 PM.

John
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217255 06/10/16 10:15 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
Member
When you say 'grow room,' I start thinking of all manner of hackwork, using fixtures salvaged from dumpsters, to grow forbidden substances.

Please note that contactors carry a specific rating for HID lighting. An ordinary 'definite purpose contactor' is not rated for HID lighting.

Likewise, fixtures need to be supplied with power within 10% of their nameplate voltage. A "240" rated fixture is not suitable for use with 208v. Not every ballast is a multi-tap, or "automatic," especially with the old, obsolete HPS lights.


Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217256 06/11/16 12:06 AM
Joined: Aug 2005
Posts: 248
T
Trick440 Offline OP
Member
I'm sorry guys I'm more residential. I put my tester on it and it was 220v or somewhere in the 200s and I just jumped to the conclusion its 208v. Is there a 3ph high leg that is 220v?

I didn't test anything in the other room. The ballasts are from what I'm told 120 or 240 automatic. Same as in the other room. http://www.galaxyballasts.com/shop/...asts/galaxy-grow-amp-electronic-ballasts

Reno, they have a bit more than salvaged fixtures from a dumpster. From the new 1200a service, RTU and all the other gadgets I'd guess they have $200k+ into it.


Shake n Bake
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217257 06/11/16 12:27 AM
Joined: Aug 2005
Posts: 248
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Trick440 Offline OP
Member
To clarify when I tested any 2 legs gave me 240v. When I tested the legs to ground, 2 read 120v and the high leg read 210v+ (I'm not sure the actual number for this high leg I seen it around 208v it stuck in my head its a 208)

Last edited by Trick440; 06/11/16 12:35 AM.

Shake n Bake
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217258 06/11/16 03:02 AM
Joined: Sep 2002
Posts: 889
N
NORCAL Offline
Member
Originally Posted by Trick440
To clarify when I tested any 2 legs gave me 240v. When I tested the legs to ground, 2 read 120v and the high leg read 210v+ (I'm not sure the actual number for this high leg I seen it around 208v it stuck in my head its a 208)



240V 3 has 2-phases 120V L-N, & what is supposed to be the B phase 208V L-N, any phase to phase should be 240V, 208Y/120V has
L-N of 120V, L-L is 208V just a note, a "slash rated" 120/240V breaker cannot be used between the high leg and any other phase, expensive 240V rated breakers have to be used.

Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217263 06/11/16 11:55 AM
Joined: Aug 2005
Posts: 248
T
Trick440 Offline OP
Member
Ok thank you for the clarification. It seems this is a Delta 120/240, 3ph has always confused me.

I'll have to check the breakers to see if its 240v rated breakers.

Do we think the improper contactors and possible wrong breakers could have fried the ballasts? Anything else I should investigate for this repair?


Shake n Bake
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217265 06/11/16 01:16 PM
Joined: Sep 2002
Posts: 889
N
NORCAL Offline
Member
Originally Posted by Trick440
Ok thank you for the clarification. It seems this is a Delta 120/240, 3ph has always confused me.

I'll have to check the breakers to see if its 240v rated breakers.

Do we think the improper contactors and possible wrong breakers could have fried the ballasts? Anything else I should investigate for this repair?



To my knowledge 240V rated breakers are only required where the high leg and another phase are being used for a 240V circuit.

Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217277 06/12/16 12:39 AM
Joined: Apr 2002
Posts: 7,178
HotLine1 Offline
Member
Interesting link to the ballasts.....

$ 279.99 gets you a 240 volt, adjustable wattage, cord & plug connected ballast. The available info at the site, includes weight, dimensions, UPC #, but there is NOT one electrical piece of info. This would be the first 'cord & plug' connected ballast I have seen.



John
Re: Contactors, 208v, 240v lighting questions. [Re: Trick440] #217279 06/12/16 03:24 AM
Joined: Jul 2004
Posts: 9,485
G
gfretwell Offline
Member
Is that a ballast for a double ended lamp?
I wonder if that is simply referring to the 410.30(G)(1) disconnect? (using a plug)



Greg Fretwell
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