The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Photo Upload Tutorial
by DanK
Yesterday at 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
1 registered (aussie240), 158 Guests and 6 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#13773 - 09/11/02 01:27 PM Little League Baseball Field
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
Please check my math:

(22) 1500 watt metal halide light standard fixtures @208 volts, 8.2 amps each. They will be balanced on a 120/208 volt, three phase, 4 wire service.

37,523 watt load divided by 208 x 1.73=104 amps.
The load would be considered continuous thus multiply by 1.25 = 130 amps total load.

Am I correct?

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#13774 - 09/11/02 01:43 PM Re: Little League Baseball Field
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
I dunno.

Try this, 21 fixtures installed so they balance out on all 3 phases equals 114.8 amps, add one more fixture on 2 phases brings the total to 123 amps multiply by 1.25 = 153.75 amps

you'll either need a 150 amp panel (your calculation) or a 200 amp panel (my calculation). The price difference is probably non-existant. The only cost that might matter would be the feeder size.
_________________________
Few things are harder to put up with than the annoyance of a good example.

Top
#13775 - 09/11/02 02:29 PM Re: Little League Baseball Field
tsolanto Offline
Member

Registered: 09/03/02
Posts: 131
Loc: Long Island NY
Frank, I did the calculation and came up with the same amperage as you did. I beleive you are correct

Top
#13776 - 09/11/02 02:36 PM Re: Little League Baseball Field
electric-ed Offline
Member

Registered: 07/08/02
Posts: 184
Loc: Canada
Each fixture - 208v x 8.2a = 1705.6 va
22 fixtures + 2 (to balance load) = 24 fixtures
1705.6 va x 24 = 40 934.4 va

40 934.4 va divide by 208 = 196.8 amps
divide by 1.73 = 113.7 amps
113.7 x 1.25 (continuous load) = 142.5 amps

Ed

Top
#13777 - 09/12/02 08:20 AM Re: Little League Baseball Field
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Frank,

Don't forget to add (10%?) for ballasts.

Top
#13778 - 09/12/02 12:05 PM Re: Little League Baseball Field
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
Is that for power factor?

Top
#13779 - 09/12/02 03:07 PM Re: Little League Baseball Field
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
Am I missing something? Why is everyone trying to change this calculation to volt-amps when Frank has stated that each fixture draws 8.2 amps?

Doing the Volt-Amp thing might be advantageuos if this load could be equally shared by all three phases, but since it can't, I feel the resulting answers are too low. The math is correct, so I'll assume that everyone slipped off their boots to use their toes and they all did their gazintas correctly.

There will be 15 fixtures on A phase x 8.2 = 123 amps, 15 fixtures on B phase x 8.2 amps = 123 amps

C phase only has 14 fixtures x 8.2 amp=114.8 amp.

125 amps x 125% = 153.75 amps, too much for 150 amp feeder or 150 amp panel.
_________________________
Few things are harder to put up with than the annoyance of a good example.

Top
#13780 - 09/12/02 05:01 PM Re: Little League Baseball Field
Chris Rudolph Offline
Member

Registered: 05/01/01
Posts: 160
Loc: Winter Park,Fl USA
A 1500 watt fixture at 208 volts will draw 7.2amps continuous.Why are we talking 8.2 amps and adding 125% for a continuous load?
What am I missing?
Chris

Top
#13781 - 09/12/02 05:39 PM Re: Little League Baseball Field
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6804
Loc: Brick, NJ USA
Chris:
A 1500 watt metal halide sport light draws 8.2 amps at 208 voltsat full illumination, and 4.70 amps starting. Source of info is Lumark/Cooper Lighting.

That is a high power factor, CWA.

HotLine1
John

PS to Frank: Put in a 200 amp feeder and panel please!
_________________________
John

Top
#13782 - 09/12/02 05:58 PM Re: Little League Baseball Field
Chris Rudolph Offline
Member

Registered: 05/01/01
Posts: 160
Loc: Winter Park,Fl USA
John,
Thanks for the info.Does Lumark/Cooper have a WEB site with tech info for their products?
Chris

Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals