208v three phase vs 240v three phase service

[spguidry]

I am in the process of installing a new service meter and panel for a building that it is to be rented. The owner said he wants 220v three phase, but has no tenents in it yet and does not know what type of equipment will be installed in the building. The building has a existance 220v 200amp single phase panel. (thats not in service now)
My plan was to leave the existance single phase panel, install a three phase 300 amp meter and panel, then sub feed existance panel from new panel. The only load on the existance panel is genral lighting and recptical circuits (three 22Ov light circuits and six 120v rectpical circuits). I talked to the power company and requested a 220v delta transformer with a center tap, which would fill both apllication, 220v three phase for equipment and 220v single phase for lighting and recpticals.
Now the problem comes in when I order material, the 220v delta center tap panel board would have to be ordered and take some time to come in. My other option would be go to a wye 208v three phase panel, which is in stock.
I know I can get 120v from the 208v wye transformer, but my concern is feeding 208v to the 220v single phase loads.
My question is would 208v work in place of 220v for the existance single phase panel or should I order the 220v panel?

thanks
spguidry

 

[Smart $]

Welcome to the forum. :thumbsup:

Before getting into more detail, can you at least narrow the type of tenant to commercial or manufacturing (light industrial).

If either is available, there are no hard rules... but IMO 208Y/120 more common to commercial, 240/120 3? to manufacturing.

 

[augie47]

I would suggest two things first off. (1) See if you can take a look at or get cut sheets on the customers equipment. Folks who don't work in the field often use "220" as a catch-all, not knowing the existence of 208 or 240. Some equipment may work on either, some is particular.
I've seen many a job go south due to the tenant/customer not knowing the difference.
(2) Confirm with POCO that either voltage is available.

Your existing panel itself will probably be o.k. at either voltage but be careful on your 3 phase panel in regard to 240.85.

 

[infinity]

As Smart stated you need to take a guess at the future tenancy. Unless there's a strong possibility of a tenant with mostly 3? loads, 208Y/120 supply would be better than a 240/120 volt, 3?, 4W Delta system.

 

[J.P.]

My initial thought is to go with the Wye system in 208/120/ IMO the wye is a more efficient system with more usable breakers.

Most equp will run on 208-240.

Being a building that is slated for rental to whomever and not knowing the type of business that will set up shop is tough.

Is it a commercial, industrial, office or likely to be a store of some kind?
What type of business are around it?

208/220/240 are often considered the same thing. Unless something has some very specific voltage requirements.

 

[norcal]

My initial thought is to go with the Wye system in 208/120/ IMO the wye is a more efficient system with more usable breakers.

Most equp will run on 208-240.

Being a building that is slated for rental to whomever and not knowing the type of business that will set up shop is tough.

Is it a commercial, industrial, office or likely to be a store of some kind?
What type of business are around it?

208/220/240 are often considered the same thing. Unless something has some very specific voltage requirements.

That statement can get one into a heap of hot water, 208 & 240V are different beasts, you do not want to operate 230/240V equipment on 208V nor 200/208V equipment on 240V. "220" is DIY lingo.

 

[kwired]

Now the problem comes in when I order material, the 220v delta center tap panel board would have to be ordered and take some time to come in. My other option would be go to a wye 208v three phase panel, which is in stock.

:?

The same panelboard is acceptable for either voltage system. The 240 volt with high leg system however can not use 120/240 rated breakers on the high leg.

 

[kingpb]

I am in the process of installing a new service meter and panel for a building that it is to be rented. The owner said he wants 220v three phase, but has no tenents in it yet and does not know what type of equipment will be installed in the building. The building has a existance 220v 200amp single phase panel. (thats not in service now)
My plan was to leave the existance single phase panel, install a three phase 300 amp meter and panel, then sub feed existance panel from new panel. The only load on the existance panel is genral lighting and recptical circuits (three 22Ov light circuits and six 120v rectpical circuits). I talked to the power company and requested a 220v delta transformer with a center tap, which would fill both apllication, 220v three phase for equipment and 220v single phase for lighting and recpticals.
Now the problem comes in when I order material, the 220v delta center tap panel board would have to be ordered and take some time to come in. My other option would be go to a wye 208v three phase panel, which is in stock.
I know I can get 120v from the 208v wye transformer, but my concern is feeding 208v to the 220v single phase loads.
My question is would 208v work in place of 220v for the existance single phase panel or should I order the 220v panel?

thanks
spguidry

I'd say the Owner has no idea what he's asking for and is using a voltage that has popped into his head. Reminds me of an old movie; "220, 221, whatever it takes".

120/240V is standard single phase (2 pole). If it is not even in service yet, then eliminate the 120/240V, bring in the 208Y/120V, set a new panel, switch over any house loads, and be done with it. The Owner wants 3-phase, use standard equipment, it will be the cheapest.

 

[kwired]

I'd say the Owner has no idea what he's asking for and is using a voltage that has popped into his head. Reminds me of an old movie; "220, 221, whatever it takes".

120/240V is standard single phase (2 pole). If it is not even in service yet, then eliminate the 120/240V, bring in the 208Y/120V, set a new panel, switch over any house loads, and be done with it. The Owner wants 3-phase, use standard equipment, it will be the cheapest.

Can't say I agree with that as a general answer. If this is office/retail/residential/institutional, or combinations of those then 208/120 is likely the best. If it is manufacturing/machine shop/ or other application with a lot of motors or resistance heating - either space heating or process heating, a 240 volt system may have some advantages over a 208 system.

 

[kingpb]

Can't say I agree with that as a general answer. If this is office/retail/residential/institutional, or combinations of those then 208/120 is likely the best. If it is manufacturing/machine shop/ or other application with a lot of motors or resistance heating - either space heating or process heating, a 240 volt system may have some advantages over a 208 system.

With an existing 120/240V panel at 200A, I was thinking that it wouldn't be an industrial setting. Been wrong once before :roll:, but typically tenants have to pay for build-out (directly or indirectly) anyway.

 

[jim dungar]

Check with the utility. It seems very few now supply anything other than 208Y/120V and 480Y/277V to new services. You need to provide your own transformers if you want a variation of 240V 3-phase.

I am currently working with a school, existing 240/120V 3P4W, that the utility is changing to 208Y/120V because they are switching to a 3-phase padmount transformer instead of single phase units in a vault. It is the customer's responsibility to 'live with' the new voltage.

 

[Jraef]

I'd say the Owner has no idea what he's asking for and is using a voltage that has popped into his head. Reminds me of an old movie; "220, 221, whatever it takes".

Love that line, it's become an internet "meme" for our business...

120/240V is standard single phase (2 pole). If it is not even in service yet, then eliminate the 120/240V, bring in the 208Y/120V, set a new panel, switch over any house loads, and be done with it. The Owner wants 3-phase, use standard equipment, it will be the cheapest.

I agree. if you go with a 240 3 phase 4 wire delta system, the 120V loading is limited. The INTENT of that service is for customers who have PREDOMINATELY 3 phase loads and need a LITTLE bit of 120V stuff for lights and outlets. If the future tenants are unknown, this actually limits his ability to rent it out.

On the other hand if you get 208Y120V 3 phase, you can use it as ALL 120V loads (with appropriate balancing of course) if that's the type of tenant(s) that move in. If it is someone who does need 3 phase, and they must have 240V 3 phase because their equipment is narrowly rated, the TENANT can (have you) boost the 208V up to 240V for those machines on an as-needed basis. In other words, using the 208Y120V service provides more flexibility to the building owner to accommodate a wider variety of potential tenants.

 

[meternerd]

I agree with the suggestion of checking with the utility. We no longer offer 120/240 4W because we are converting most of our commercial services to underground, and those transformers are special order and much more expensive. You need to verify that any existing customers or customers with older equipment can use 208. Nameplates of equipment should tell you. Machines rated for 240 only may have trouble on 208. Those rated 220 probably won't because most utilities usually supply 212 to 214 anyway. Unless it's a very large facility with VERY specific needs, the answer from the utility is usually..."deal with it".

 

[spguidry]

Thanks for all the feedback, lots of intresting suggestions and ideas. I checked with the POCO and both 120/208v and 120/240 three phase power is availabe. One of the reasons I was leaning toward 120/240v three phase was of the existing 240 single phase panel. If I go this route I would just have to subfeed old panel from new panel. If I go 120/208 then I would have to reroute pipe and pull wire for these circuits to the new panel, and possible have to change out the light fixtures, which may or maynot work on 208v. Just trying to keep it simple.

I know that the 120/208v and 120/240v panel boards are same lay out, but my local supplier said Simens would not warranty a 120/208v panel board for use as 120/240v panel board with a high leg without beefing up the wild leg bus bar, which means it has to be ordered, which drives up the cost and delays the project (four to six weeks). I am now checking with different sources for a 120/240v panel board, and it looks promising there will be one in stock, will find out in the morning.

The building was used a warehouse with a small office in it. It is going to marketed for comercial/industrial use.

Thanks for everybodies input
spguidry

 

[Smart $]

.... One of the reasons I was leaning toward 120/240v three phase was of the existing 240 single phase panel. If I go this route I would just have to subfeed old panel from new panel. If I go 120/208 then I would have to reroute pipe and pull wire for these circuits to the new panel, and possible have to change out the light fixtures, which may or maynot work on 208v. ...

Whichever way you go will not change what you can do with the existing panel. A 120/240 panel is suitable for either 120/240 or 120/208.

However, you are correct about the lighting possibly not being compatible with 120/208 if they are 240V fixtures. Some ballasted lighting is compatible with 208 but may have to be rewired. If 120V fixtures, they would be fine either way.

Is the owner looking at just one tenant or possibly more than one? If more than one, may want to have separate metering, panels, lighting, etc.

 

[jim dungar]

....but my local supplier said Simens would not warranty a 120/208v panel board for use as 120/240v panel board with a high leg without beefing up the wild leg bus bar, which means it has to be ordered, which drives up the cost and delays the project (four to six weeks).

You need to talk to someone else, unless you are buying a 3-phase panelboard that is built with only 120V to ground insulation (which I don't think I have ever seen), there should not be any busbar changes. By far and away the most common problem with 240/120V 3-phase is only with the 2-pole breakers connected to the high leg, which are usually special order.

 

[kwired]

With an existing 120/240V panel at 200A, I was thinking that it wouldn't be an industrial setting. Been wrong once before :roll:, but typically tenants have to pay for build-out (directly or indirectly) anyway.

OP has since clarified some - I kind of took it from OP that there is no definite future tenant(s), which he still more or less has confirmed.

Love that line, it's become an internet "meme" for our business...

I agree. if you go with a 240 3 phase 4 wire delta system, the 120V loading is limited. The INTENT of that service is for customers who have PREDOMINATELY 3 phase loads and need a LITTLE bit of 120V stuff for lights and outlets. If the future tenants are unknown, this actually limits his ability to rent it out.

On the other hand if you get 208Y120V 3 phase, you can use it as ALL 120V loads (with appropriate balancing of course) if that's the type of tenant(s) that move in. If it is someone who does need 3 phase, and they must have 240V 3 phase because their equipment is narrowly rated, the TENANT can (have you) boost the 208V up to 240V for those machines on an as-needed basis. In other words, using the 208Y120V service provides more flexibility to the building owner to accommodate a wider variety of potential tenants.

Open delta systems are commonly used when there is a lot of 120/240 single phase load and limited three phase load.
Open delta is also common for limited specific load applications like a pumping station with little or no other loads at the service location, is easy and relatively inexpensive to build out of same transformers the POCO has in stock for single phase services. They can also have a larger unit for the 120/240 phase and use smaller units for the other(s) if the three phase load is limited.

I find it amusing that all these people are saying that POCO's are getting rid of 120/240 delta systems, yet there are new services in this area going up all the time with this configuration, majority of them that are full delta with three equal sized transformers are for grain storage bin locations but is not limited to those either, and the open delta can appear anywhere if the conditions dictate that it is going to be the best cost method.

 

[jim dungar]

I find it amusing that all these people are saying that POCO's are getting rid of 120/240 delta systems...

Be amused all you want. But, the truth is that 240/120V 3-phase padmount transformers are expensive and are not commonly purchased by utilities, therefore in areas with underground padmount services 240/120V is not normally available.

Locales serviced by 'pole-top' style units do not have added expense so they are relatively easy to supply.

However, you cannot assume the utility will continue to provide what they have always done.

This is typical of all major utilities in Wisconsin: Alliant Energy says "When the demand of an existing three?phase 120/240Volt Delta, four?wire customer exceeds the rated capacity of the Customer?s existing service entrance, the Customer shall convert to a 120/208 or a 277/480Volt three?phase, four?wire service."

 

[kwired]

Be amused all you want. But, the truth is that 240/120V 3-phase padmount transformers are expensive and are not commonly purchased by utilities, therefore in areas with underground padmount services 240/120V is not normally available.

Locales serviced by 'pole-top' style units do not have added expense so they are relatively easy to supply.

However, you cannot assume the utility will continue to provide what they have always done.

This is typical of all major utilities in Wisconsin: Alliant Energy says "When the demand of an existing three?phase 120/240Volt Delta, four?wire customer exceeds the rated capacity of the Customer?s existing service entrance, the Customer shall convert to a 120/208 or a 277/480Volt three?phase, four?wire service."

I did know that 240/120 3 phase padmounts are expensive - less demand for them probably the main reason. I have also seen single phase padmounts connected together to make a three phase bank, though that is done less than it used to be. For the most part those services around here with that supply system are either existing or for new services you are getting pole mounted transformers, even if it supplied via an underground method.

Sure you can't assume a utility will continue to provide what they have always done. That could even include refusal to continue to supply 120/240 single phase to their customers, but that would not be a good decision to most of their consumers. I don't see 120/240 volt delta systems anything that will disappear anytime soon in this area, in fact the rural systems are still commonly providing a high leg open delta 480 volt system for irrigation services that have limited load.

Nobody serves customers with corner grounded systems anymore, they all stopped that practice 20-25 years ago, I ran into a few of those when I was first starting in this trade, but they have all been eliminated.