Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-01-2010, 05:41 PM   #1
Newbie
 
Join Date: Sep 2010
Posts: 5
Rewards Points: 10
Default

3PH 4W Delta Help!


I want to create a subpanel from the service panel...used for single phase 120/240


is there a benefit from using Pa and Pb when powering 240 or is it the same efficiency when using Pa and Pc?


I have 3 xfmrs on the pole 15 15 and 25
does that mean a certain phase can handle more?


TIA!

hailo is offline   Reply With Quote
Old 09-01-2010, 06:53 PM   #2
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,864
Rewards Points: 2,032
Default

3PH 4W Delta Help!


Please call an electrician. Being commercial this is NOT a DIY job.

Speedy Petey is online now   Reply With Quote
Old 09-01-2010, 07:53 PM   #3
" Euro " electrician
 
frenchelectrican's Avatar
 
Join Date: Apr 2006
Location: WI & France { in France for now }
Posts: 5,369
Rewards Points: 2,000
Default

3PH 4W Delta Help!


If this is in the commercal building I really recommend that you call the electrician to deal with this.

There are quite few ways to deal with Delta system and they are pretty tricky to deal if not addressed right.

If this is in resdential { home } I really suggest that you take a photo of the load centre and we will go from there.

There are few way it can be done but I think it best if you take the photo first because there is about 2 or 3 diffrent way to deal with delta system.

And by modern NEC code the Delta wild leg will have orange conductor or marking { very old delta system will have red marking instead of orange }

so again please do it in safe manner.

Merci.
Marc
frenchelectrican is offline   Reply With Quote
Old 09-01-2010, 10:01 PM   #4
Newbie
 
Join Date: Sep 2010
Posts: 5
Rewards Points: 10
Default

3PH 4W Delta Help!


Quote:
Originally Posted by Speedy Petey View Post
Please call an electrician. Being commercial this is NOT a DIY job.
Thanks for the response....but im certian this is not out of my scope...
If you could assist in the matter, that would be great...

Quote:
Originally Posted by frenchelectrican View Post
If this is in the commercal building I really recommend that you call the electrician to deal with this.

There are quite few ways to deal with Delta system and they are pretty tricky to deal if not addressed right.

If this is in resdential { home } I really suggest that you take a photo of the load centre and we will go from there.

There are few way it can be done but I think it best if you take the photo first because there is about 2 or 3 diffrent way to deal with delta system.

And by modern NEC code the Delta wild leg will have orange conductor or marking { very old delta system will have red marking instead of orange }

so again please do it in safe manner.

Merci.
Marc
Thanks Marc,
this is a commercial...and is a delta system....thanks for the safety tips!

im not sure what the load centre pic is for? if you like i can post....

there is no question in regards to the type of power....

Im interested in load balancing....and the ampacity of each phase....(edit: can one phase handle a larger load then the other 2)
hailo is offline   Reply With Quote
Old 09-01-2010, 10:20 PM   #5
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,859
Rewards Points: 2,114
Default

3PH 4W Delta Help!


I agree with Petey on this.
Regardless of the skills you posses, this is a DIY forum, and this is not a DIY job!
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 09-01-2010, 10:28 PM   #6
Newbie
 
Join Date: Sep 2010
Posts: 5
Rewards Points: 10
Default

3PH 4W Delta Help!


Quote:
Originally Posted by jbfan View Post
I agree with Petey on this.
Regardless of the skills you posses, this is a DIY forum, and this is not a DIY job!
Thanks for the reply!

Since im not an electrician by trade this is considered DIY....
hailo is offline   Reply With Quote
Old 09-01-2010, 10:34 PM   #7
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,864
Rewards Points: 2,032
Default

3PH 4W Delta Help!


Quote:
Originally Posted by hailo View Post
Thanks for the response....but im certian this is not out of my scope...
The why are you coming to a DIY site for help?

This is a commercial/industrial setting. This IS out of the scope of anyone but a qualified electrician.

I don't doubt that you can strip the wire and tighten a screw on a breaker, but knowing what you are doing and why is the key. Coming to a site like this with a question like this proves this is out of your scope.
Speedy Petey is online now   Reply With Quote
Old 09-01-2010, 10:42 PM   #8
Newbie
 
Join Date: Sep 2010
Posts: 5
Rewards Points: 10
Default

3PH 4W Delta Help!


Quote:
Originally Posted by Speedy Petey View Post
The why are you coming to a DIY site for help?

This is a commercial/industrial setting. This IS out of the scope of anyone but a qualified electrician.

I don't doubt that you can strip the wire and tighten a screw on a breaker, but knowing what you are doing and why is the key. Coming to a site like this with a question like this proves this is out of your scope.
if you dont want to offer your assistance or cant answer the question, that is fine...maybe someone else can...

To rephrase the questions....for educational purposes....


is there a benefit from using the high leg in a 240 (edit:single phase )application?

why the odball xfmr exists if all 3 phases are equal?
hailo is offline   Reply With Quote
Old 09-02-2010, 12:20 AM   #9
" Euro " electrician
 
frenchelectrican's Avatar
 
Join Date: Apr 2006
Location: WI & France { in France for now }
Posts: 5,369
Rewards Points: 2,000
Default

3PH 4W Delta Help!


Quote:
Originally Posted by hailo View Post
if you dont want to offer your assistance or cant answer the question, that is fine...maybe someone else can...
First off., Myself and Speedy ask you this question and we make it clear this is a DIY fourm and by the codes and states laws the commercal building it have to be done by electricians there are quite a bit of codes it have to deal compared to resdentail side.

I am not being mean but there are some area I will have to draw a line where this will stop and this is mainly for safety reason due the commercal load centre will have more capaity than resdentail load centre will have.


Quote:
Originally Posted by hailo View Post
To rephrase the questions....for educational purposes....


is there a benefit from using the high leg in a 240 (edit:single phase )application?

why the odball xfmr exists if all 3 phases are equal?
To use the high leg it only work very well with line to line load that it { that for any equiment that do not need netural it will work any phase }

If you used the high leg for line to netural load it will result damaged equiment { especaily if wired for 120 volt loads }

And you will need specal rating breakers on delta system escpally on wild leg side { you must use the straght voltage rated breaker not one with slashed rated like example 120/240 volts that will not allowed on wild side it have to be 240 volts only }

The reason why delta service is used for both single and three phase loads and there is no differnce on which load is majtory as long the transfomers are sized properly it can work like majtory of single phase load with small three phase load or vice versa.

Again in final part due you mention it is a commercal you have to get electrician to come out and deal with load balnceing { it can get tricky if not carefull }

Merci.
Marc
frenchelectrican is offline   Reply With Quote
Old 09-02-2010, 08:31 AM   #10
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,964
Rewards Points: 2,024
Default

3PH 4W Delta Help!


If you have 240 volt equipment and a 240 volt delta 3 phase with asymmetrical neutral and high leg, it is usually better to connect the 240 volt only equipment to the high leg. Let's call the high leg B and the other two legs A and C. For modest 240 volt requirements, connect the 240 volt branch circuits more or less equally between A and B and between C and B. Connect the 120 volt branch circuits more or less equally between A and neutral and between C and neutral. Connect the equipment and single phase multiwire branch circuits that use both 120 and 240 volts using A, C, and neutral.

This more or less balances the total load among all three legs. If you do not have 240 volt only equipment (no neutral in the power cord), then you should balance the load only between A and C.

Do not run the high leg to a subpanel unless circuits to three phase equipment or 240 volt only equipment will be hooked up there. The amateur desiring subpanels may prefer to install separate subpanels for 120/240 volt circuits (with neutral and no high leg) and for 240 volt only circuits (high leg and one or both of the other legs and no neutral).

You need to be extra careful putting breakers in a panel with a high leg 3 phase supply. Just moving a breaker up or down one step in the panel can cause disastrous results if you land on the high leg by mistake.

Although the B label is usually put on the high leg, do not assume this is the case. Measure the hot to neutral voltage each time just to be sure.

Do you know which transformer is the oddball? I would suspect that the larger transformer is connected to the A and C legs where all the 120 volt loads run off of it and also some of the 240 volt only loads are connected between A and C. Either that, or the oddball was put there because one of the same size was not available at the time.

Formulas, not simple addition and subtraction, are needed to figure out the load on each of the legs A, B, and C in a 3 phase system.
__________________
Forget super sized fries. The Washington Redskins could promote healthy eating with First Lady Obama by choosing a (red skinned) turnip for a mascot.

Last edited by AllanJ; 09-02-2010 at 09:21 AM.
AllanJ is offline   Reply With Quote
Old 09-02-2010, 09:52 PM   #11
Newbie
 
Join Date: Sep 2010
Posts: 5
Rewards Points: 10
Default

3PH 4W Delta Help!


Thanks Marc and AllanJ!

Keep it up! Great assets to this forum!

hailo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Delta Ball Joint shower arm adapter??? nic3456 Plumbing 3 11-10-2010 10:01 AM
Glacier Bay, Peerless, Delta Yoyizit Plumbing 2 03-11-2009 11:20 AM
concrete basement - installing laminate on delta SDG Flooring 1 12-29-2008 08:10 PM
wiring a 220 volt delta unisaw and delta x5 planer naveall Electrical 13 10-30-2008 01:30 PM
Delta table saw blade guard problem RDS Tools 7 03-07-2008 03:29 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.