120/240 v single phase panel

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GoldDigger said:
You have still not clarified what kind of loads will be fed from the 120/240 panelboard.
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Sorry again for that.

I have no 240V loads fed from 240/120v single phase panelboards. They are either 120 or 208V rated at this time. However what if in future someone places 240V load then what?

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GoldDigger said:
You have still not clarified what kind of loads will be fed from the 120/240 panelboard.
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Well if the feeder to the panel is 120/208 volt 1ph , wouldn't it make sense that, that's all they're going to get out of it ?

JAP>
 
He indicated this was a new installation.

He's not re feeding an existing 120/240v 1ph panel.

JAP>
 
GoldDigger said:
The OP might. He asked about feeding a 120/240 three wire single phase panel, he did not specify that there were only line to neutral loads on that panel.
A complete answer to his question would have to note that it could not drive 240V loads unless they were also rated for operation at 208V.
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He actually asked if he could feed a 120/240v three wire single phase panel with 120/208v three wire single phase, period, and the answer is yes.




JAP>
 
codequestion said:
Sorry again for that.

I have no 240V loads fed from 240/120v single phase panelboards. They are either 120 or 208V rated at this time. However what if in future someone places 240V load then what?

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They need to be smart enough to know that they will need a boost transformer on the branch circuit coming out of the 208v subpanel.

JAP>
 
jap said:
He actually asked if he could feed a 120/240v three wire single phase panel with 120/208v three wire single phase, period, and the answer is yes.
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Except it wouldn't be single phase. Maybe that doesn't matter for his application.
 
It seems some of you like to argue just to argue.

Yes, it's okay to feed a 1-ph panel from a 3-ph source, as long as it's understood that the line-to-line voltage is 208 and not 240.

It;s that simple.
 
electrofelon said:
I think I mentioned this to you last time this came up, but here in the states we call two phases, even if there is a neutral, single phase.
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Yes, I know that's what you call it and I don't mind that you do. But the two line to neutral (120-0V) are phase displaced by 120 deg.
I'm not arguing for the sake of it. Just confirming what I see as the arrangement.
 
codequestion said:
Sorry for the confusion. To put it more clearly:

I have 480/277V transformer primary and 208/120V transformer secondary three phase. The transformer secondary feeds 208V/120V three phase panelboard.

The 208V/120V three phase panelboard has single phase 2 pole feeder circuit breaker which feeds to 240/120V single phase panelboard.

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panelboard is rated for up to 240 volts, you are supplying it with 208 - only way you will get 240 is with a transformation of some sort.

codequestion said:
Sorry again for that.

I have no 240V loads fed from 240/120v single phase panelboards. They are either 120 or 208V rated at this time. However what if in future someone places 240V load then what?

Sent from my SM-G935U using Tapatalk
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Many things are rated for use at either 208 or 240, some at different power rating though. If you must have 240 you will need transformation for that particular load.
 
Just to clarify:

A standard 3-wire system is going to be 120/240V and a standard 4-wire system is going to be 208Y/120V.

If you feed a 3-wire system from a standard 4-wire system, you get a modification as 120/208Y.

At least that's according to IEEE Std C84.1. But hey, what do they know. :eek:
 
kingpb said:
Just to clarify:

A standard 3-wire system is going to be 120/240V and a standard 4-wire system is going to be 208Y/120V.

If you feed a 3-wire system from a standard 4-wire system, you get a modification as 120/208Y.

At least that's according to IEEE Std C84.1. But hey, what do they know. :eek:
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So I guess you don't consider a 120/240v or 480/277v 4 wire system standard.


JAP>
 
jap said:
So I guess you don't consider a 120/240v or 480/277v 4 wire system standard.


JAP>
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What part of 120/240V being a STANDARD 3-wire system didn't you read?

And yes a 408Y/277V is a standard voltage, but since nowhere in the entire post has 408Y/277V ever been questioned, I was not inclined to interject extraneous information to convolute the topic.

I guess I could have also listed 4160V, 13.8KV, 69KV, 240/120V (H-leg delta) 12470Y/7200V. How many do you want mentioned?
 
kingpb said:
but since nowhere in the entire post has 408Y/277V ever been questioned, I was not inclined to interject extraneous information to convolute the topic.
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I Don't remember A standard 3-wire system being 120/240V and a standard 4-wire system being 208Y/120V ever being questioned either.


JAP>
 
jap said:
I Don't remember A standard 3-wire system being 120/240V and a standard 4-wire system being 208Y/120V ever being questioned either.


JAP>
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Simply "clarifying" improperly stated voltages as mentioned in Posts #1, #6, #8, #16, and #22; at least according to IEEE C84.1.
 
kingpb said:
Simply "clarifying" improperly stated voltages as mentioned in Posts #1, #6, #8, #16, and #22; at least according to IEEE C84.1.
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So what do you properly call voltages that feed 120/208v 1ph panels that are fed from a 120/208v Y 3ph panel?


JAP>
 
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