# 3P3W High Leg Delta Power 240V



## walkerj (May 13, 2007)

You need a delta wye. 

If it doesn't work, you wired it wrong.


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## l0sts0ul (May 7, 2011)

Problem is, that is not readily available to me. I've been looking for a week now. 

I cannot use the neutral on the wye side either, I can only use the 3phase 208v, ground the XO. 

a wye/wye is an option, or a auto trans. 

The only options I have is a Delta/Wye, or a Wye/Wye. I just don't hook up the XO on the primary, but ground the XO on the secondary, do you agree or disagree?

thanks


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## stuiec (Sep 25, 2010)

EPCOR is pretty keen on getting rid of those, have you considered a service change?


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## l0sts0ul (May 7, 2011)

customer doesnt' want to cover the cost of the upgrade. Due to the layout of the building, and the services installed, the only option really that is cost effective would be install a new pole, and run either 208/120v or 600v to the building as an addition. 

Still a 10-20k job+, and my costs, and this would have to be an addition.


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## walkerj (May 13, 2007)

If it takes more than 2 weeks to get that transformer you need to find a new supplier. 
This is a common transformer.


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## stuiec (Sep 25, 2010)

walkerj said:


> If it takes more than 2 weeks to get that transformer you need to find a new supplier.
> This is a common transformer.


Not alot of High Leg services in this city.


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## walkerj (May 13, 2007)

stuiec said:


> Not alot of High Leg services in this city.


I'm sure there isn't one on the shelf at the supply house but the factory likely has one.


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## l0sts0ul (May 7, 2011)

All the factories up here that make our transformers are closed for two weeks due to some 2 week holiday In Quebec. Then they want 3 weeks to build and ship. Bad timing if nothing else I guess. 

We have 4 major manufacturers in Canada and three are in Quebec.


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## stuiec (Sep 25, 2010)

That's right, doesn't all of Quebec take their 'forced' holiday at the same time?


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## l0sts0ul (May 7, 2011)

I guess. But either way, it still screws me and my customer over. 

And for the record, a 240/208 delta/wye transformer is not that common up here. We would usually go up or down from 600. High leg delta is only in a few areas of Edmonton, for some its fine, but for finicky VFD units, they are a pain in the arse.


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## stuiec (Sep 25, 2010)

Have you tried Canadian Industrial? Falvo? They are used, but tested I believe...


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## l0sts0ul (May 7, 2011)

Yup no stock. New only and they are out of quebec


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## don_resqcapt19 (Jul 18, 2010)

l0sts0ul said:


> Hey all,
> 
> I have a 200A 3phase 3wire high leg delta 240V Service.
> ...


That is not possible. You have to have a forth wire for a three phase high leg delta.


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## l0sts0ul (May 7, 2011)

There is a bonding conductor but that's it.


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## Vintage Sounds (Oct 23, 2009)

Even Rex can't hook you up huh?


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## l0sts0ul (May 7, 2011)

They manufacture in QC as well.


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## Vintage Sounds (Oct 23, 2009)

l0sts0ul said:


> They manufacture in QC as well.


Not so sure about that, unless they have a second factory in Quebec. I used to live near the Rex plant in Concord ON and picked up from there a few times too.


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## l0sts0ul (May 7, 2011)

Wholesaler out here are quoting out of QC


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## l0sts0ul (May 7, 2011)

So, I need to clarify something. (This could be classed as Canadian electrical code as well, but the physics of this problem are what intrigue me).

I have a 240V High Leg Delta. The main reason I am looking for this transformer is I have a crane that is rated at 230V, BUT, the Phase sequencer measures from each leg to ground to allow the 3phase motor on the crane to run. Therefore when it measures between the high leg and the ground, it see about 208V not the 120v it sees on the on the other 2 phases (which are ground being a high leg), and will not run. 

That is problem #1. Problem #2 is, they have some equipment that needs to see 208v only, so this requires a 240v to 208V transformer (auto would normally work, but there is an exception) 

I would like to solve both of these problems with 1 fell swoop, and the best solution I have mustered is the following.

1. 240v - 120v/208v (delta/wye) and run a ground from the XO all the way back to the main system ground and high press it to that for the ground. (I am under the understanding that the equipment bond from the panel is not sufficient to meet code. other option is a ground fault detection, but I think the cable run in this situation is sufficient, being it only has to be a #6)

2. 240v/120v -208v/120v (wye wye) and leave the neutral on the high side alone, and run the XO to the system ground as mentioned before.

PLease let me know what you think. I Would like to understand the physics behind WHY the XO has to be grounded here. I understand how it affects the centre point of theWYE on the secondary to even out loads, but I want to know how.

I need to know which of these will work (i believe both will, but I Want confirmation). 

I need to order this ASAP, but i'm waiting 3-4 weeks no matter what.

thanks again for all your help.


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## l0sts0ul (May 7, 2011)

Bump please. Sorry to do this.


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## Big John (May 23, 2010)

Install a 240Δ:208Y, bond the X0 and connect it to your existing grounding electrode system.

You bond the X0 to create a fault-current return path if you have a ground fault.

You connect to the GES to be sure the system voltage stays stable during operation or fault conditions.


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## IslandWire (Aug 3, 2013)

You should use the following and you will get a good Wye bank 208 output. 

Primary
240 Delta(3 wire connection) Ground the enclosure.

Secondary
208Y/120(4 wire connection) Bond the secondary N to G

It doesn't matter if your Primary feed has a neutral, just don't use it. The transformer will create the neutral on the Secondary that properly references the 3 phases on the Wye bank.


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