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
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
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 15
HotLine1 10
Trumpy 8
Texas_Ranger 8
sparkyinak 7
Who's Online
2 registered (NORCAL, sparkyinak), 205 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#127547 - 08/22/01 05:43 PM 3 phase total power
aldav53 Offline
Member

Registered: 08/22/01
Posts: 547
Loc: Chandler, AZ USA
When measuring each leg on a 3 phase service, if it is a 200amp panel and the feeder wire is good for 200 amps, that would mean each leg is good for 200amps measuring individually with an amp clamp. Is this correct? If it is, does that mean you have a total of 600 amps?, or is that just the relationship between the phasing in the transformer, and actually only have a 200amp total.
Hope this makes sense..
_________________________
The Golden Rule - "The man with the gold makes the rule"

Top
#127548 - 08/22/01 05:57 PM Re: 3 phase total power
electure Offline

Member

Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA
If you have a 208 volt system, you'll have 72051 voltamps available. If it's a 120/208 system, you will have a total of 600 amps of 120 volt power available.
If a 480 system you'll have 166272 voltamps available. If a 277/480 system this will give you a total of 600 amps of 277

Top
#127549 - 08/22/01 06:25 PM Re: 3 phase total power
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Electures explanation is a good one. I like to keep it simple - the conventional definition is a 3 phase 200 amp service. Total available (apparent) power = V x A x 1.73

[This message has been edited by Redsy (edited 08-22-2001).]

Top
#127550 - 08/22/01 06:54 PM Re: 3 phase total power
Anonymous
Unregistered


Note: 1.73 is really the square root of 3.

Top
#127551 - 08/24/01 03:34 AM Re: 3 phase total power
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
"If it is, does that mean you have a total of 600 amps"? My question is: Wouldn't there actually be 600 amps available for example if all loads were 120 volts, line to neutral? I know it would not be practical. However, wouldn't it be possible?

Top
#127552 - 08/24/01 03:41 AM Re: 3 phase total power
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
I forgot to mention in my above example the service is: 120/208V, 3Ph, 4W, 200 amps.

Top
#127553 - 08/24/01 05:22 AM Re: 3 phase total power
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
I still say no. It would be a balanced 3 phase 200 amp load, equally divided between the phases at 200 amps each. However, you could supply 20 10 amp 120 volt loads on each leg. This would translate 600 a. x 120 v. which puts you back to 72,000 watts.

Top



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