Confusion with 208v to my new studio

[akuma13]

I just moved into a new building and I'm having some trouble adding a 240v line in for my stackable washer and dryer.

When I test the incoming lines to my breaker panel (2 brown hot and one white/neutral ) they read 240v across the two hot, 120v across the left hot to neutral, and 215v across the right hot to neutral...

Does this mean I have 3 phase? I don't see a 3rd hot line coming in...

I added a new 240v 30amp line for the washer and dryer unit - the manual states that it will work on 208v but that it will take longer to dry.

This unit usually takes 240v in for the dryer via one cord and splits off 120v for the washer inside the machine.

When I read the voltage at the back of the washer (3 bolts and a ground bolt to the side) I get 240v from hot to hot, 120v from left hot to neutral, and the 208v reading again on the right to neutral.

As you might guess the machine doesn't operate on this voltage.

I'm trying to solve this the best way possible - I'm considering 3 options.

#1 - get a step down converter for the 208v side and drop it to 120v and hope that it will function with the other 120v coming out of the main panel with the proper phase to create a conventional 240v line with 120v potential for the washer.

#2 - buck boost the 208v to 240v - though I'm not sure on how this would effect the 120v potential or how to approach connecting this to the machine.

#3 - I think I've read something about creating a sub panel off the main panel that was capable of creating a standard 240v of it's own - but I don't see how since it seems it would lack the opposing phase required.

Thanks in advance for any input or suggestions - my move and down size was related to the foreclosure of my home of 10 years - option #4 - hiring a professional isn't a viable option at the moment.

P. Warren

 

[tcmtech]

It means you have part of a three phase system. Just two legs of it. If you need 240 volt and you have 240 volt I don't see where the concern is. Typically any machine or appliance that use a 240 volt source and only have a three prong plug use the ground for just a ground and nothing else.

Connect your two power leads of your appliance across the 240 volt feed lines and the ground pin to the common/ground point and don't worry about it.

 

[akuma13]

Thank you for the quick response - I was wondering if that was the case (2 of 3 legs)...

I thought about doing it the way you said but I wasn't sure how to carry out the required grounding since measuring either of the hot lines to ground reduced them to 120v or 208v.. won't returning a ground from the machine's neutral to the box reduce them in the same manner I measured? I'll give it a shot in just a bit - thanks again!

 

[#12]

I think the part about the washer needing 120 volts is a real problem. This calls for an electrician to provide proper voltages. Ask the building owner to provide proper electrical service for a residence.

 

[akuma13]

That's what I thought might be tricky - usually you have two 120v lines coming in and I think it just splits one for the washer half and uses the 240v for the dryer... Another option might be to split the 120v portion off and use a second cord to power it from a nearby outlet. Its a mixed zone building - he's allowing me to make upgrades but they will all be at my expense.

 

[tcmtech]

At most if the machine did need a specific 120 volt source all you need to do is measure the voltage through the machine to the common line. If you get near zero volts nothing in the machine needs 120 volt power. If you either get 120 volts or 208 volts then its just a matter of choosing which power lead is connected to the supply line that gives you 120 volts in reference to the common point.

What the two power lines supply is the voltage that the circuits that are connected across them get. If no other internal circuits are between either line and the ground then the ground is just a safety line and not a power carrying line so its voltage differential between it and the power lines in of no concern.

Unless its a really old machine all modern machines that have a need for both 120 and 240 volts have 4 wire power connection systems not three wire.

 

[Reloadron]

Based on what you posted I am going to venture a guess that your building power or at least your panel you measured is configured like the attached drawing. This is a 3 phase delta with a wild leg (sometimes called other names for the leg). That is the only way I can see you getting the numbers you see. That would explain panel neutral to one leg as 120 and another leg to neutral as 208 as well as leg to leg as 240 volts.

What I don't get is why the panel is configured that way. Generally you would have the two phases common to the neutral run to the panel for 120-0-120 rather than the high leg on one side giving you 120-0-208. The only need I could see is if they used 1/2 the panel for 208 volt lighting? Beats me? Additionally you mentioned two Brown wires while in a high leg configuration generally orange is used to denote the high leg (phase B in my attached cartoon). Not to say it is always done that way.

Anyway as tcmtech suggest what you could do is place the leg of your machine needing 120 volts on the 120 volt leg to neutral. You will still have your 240 volts line to line (phase to phase). You just need to be damn sure you get the right side or you will feed 208 volts to the 120 volt requirements of your machine. That or find the source for the panel (likely a transformer if a large facility) and run your machine off what would be phases A and C using the phase center tapped neutral. That would involve a new service line and disconnect. However, given the choice I would use tcmtech's suggestion.

Anyway, that is my guess as to why you see what you see. Don't take it as gospel.

<EDIT> After reading your post again when it comes to washer / drier systems the washer is generally 120 VAC but the drier uses 120 VAC for the motor and 240 VAC for the heater elements. Thus the longer drying time. Is this building commercial or residential? Anyway,if I am guessing right as to the configuration you will need 120 VAC for the drier motor. </EDIT>

Ron

 

[akuma13]

I'll give that a try... I think the reason for the split voltage is that its basically 2 devices stacked... washers can run on 120v and the gas dryers do but the electric dryers (like this one) require the extra power... I think whirlpool gears them up for 120v so they can use many of the same parts across gas and electric models..

At most if the machine did need a specific 120 volt source all you need to do is measure the voltage through the machine to the common line. If you get near zero volts nothing in the machine needs 120 volt power. If you either get 120 volts or 208 volts then its just a matter of choosing which power lead is connected to the supply line that gives you 120 volts in reference to the common point.

What the two power lines supply is the voltage that the circuits that are connected across them get. If no other internal circuits are between either line and the ground then the ground is just a safety line and not a power carrying line so its voltage differential between it and the power lines in of no concern.

Unless its a really old machine all modern machines that have a need for both 120 and 240 volts have 4 wire power connection systems not three wire.

 

[Reloadron]

I'll give that a try... I think the reason for the split voltage is that its basically 2 devices stacked... washers can run on 120v and the gas dryers do but the electric dryers (like this one) require the extra power... I think whirlpool gears them up for 120v so they can use many of the same parts across gas and electric models..

The reason for the 240 volts is the heater elements in the drier. That is why they say 208 would work but longer drying times. The 208 would be based on a 208 wye configuration where phase to phase is 208 and any phase to neutral is 120 volts. The 120 volts is generally to run the motor in the drier. A drier using 120 volt heater elements would draw twice the current of 240 volt elements to get the same heat. Thus the need for larger gauge wire to feed it and a higher current 120 volt source to feed it for the same heat.

Hope that helps
Ron

 

[akuma13]

Hi Ron, thank you for that! yes I think you nailed it... and yes I am in a mixed-zone warehouse/lioft (read:bare bones) space in downtown LA. A concrete vault with nothing in it but light fixtures when I moved in... The building is geared (or was) up for light manufacturing and fabrication.

I think the contractor that the owner used to add my panel (which is a sub panel of the unit downstairs) made an arbitrary decision and didn't intentionally send me The Crazyleg... or there may have been some logistic reason behind it. Since my utilities are rolled into rent with a flat rate, I'm inclined not to reveal the additional power drawing upgrades right away.

I did get his permission, but I'd prefer not to have a renegotiation conversation with him just yet.

What are your thoughts on using a step down converter to bring the 208v down to match the other 120v side? I wonder what it will do to the phase relationship?

Based on the responses here I tried pulling the power off each branch to replicate the 240v measuement I got when reading the two brown wires at the panel- and the voltage across the two hots on the back of the dryer read 240v... and right side to ground came out 120v...

*drum roll*

I though it was too good to be true when MRS CRAZYLEGS reared her ugly head right there on the back of my dryer... 215v and a punch in the face.

I'm still thinking about making a sub panel from the "good" side... and wondering if there's any way to split and reverse phase in such a way that a 240v could be made when paired back to origin I'll probably only be pulling a 20a load at max when drying.

I've also heard some interesting things about buck/boost transformers and balancing the line with a modest multiplier. Not sure what effect this would have on phase or the relationship with the other "good" leg.

For now I'll go see about separating the 120v requirement I hope it's as easy as just taking the good side and running with it.

Thanks again to all that responded.

Paul

Based on what you posted I am going to venture a guess that your building power or at least your panel you measured is configured like the attached drawing. This is a 3 phase delta with a wild leg (sometimes called other names for the leg). That is the only way I can see you getting the numbers you see. That would explain panel neutral to one leg as 120 and another leg to neutral as 208 as well as leg to leg as 240 volts.

What I don't get is why the panel is configured that way. Generally you would have the two phases common to the neutral run to the panel for 120-0-120 rather than the high leg on one side giving you 120-0-208. The only need I could see is if they used 1/2 the panel for 208 volt lighting? Beats me? Additionally you mentioned two Brown wires while in a high leg configuration generally orange is used to denote the high leg (phase B in my attached cartoon). Not to say it is always done that way.

Anyway as tcmtech suggest what you could do is place the leg of your machine needing 120 volts on the 120 volt leg to neutral. You will still have your 240 volts line to line (phase to phase). You just need to be damn sure you get the right side or you will feed 208 volts to the 120 volt requirements of your machine. That or find the source for the panel (likely a transformer if a large facility) and run your machine off what would be phases A and C using the phase center tapped neutral. That would involve a new service line and disconnect. However, given the choice I would use tcmtech's suggestion.

Anyway, that is my guess as to why you see what you see. Don't take it as gospel.

<EDIT> After reading your post again when it comes to washer / drier systems the washer is generally 120 VAC but the drier uses 120 VAC for the motor and 240 VAC for the heater elements. Thus the longer drying time. Is this building commercial or residential? Anyway,if I am guessing right as to the configuration you will need 120 VAC for the drier motor. </EDIT>

Ron

 

[akuma13]

You can't hide from Mrs. Crazylegs... even though I seemed safe and home free, she was there waiting and lurking in all two hundred and eight shadows. It sounds dangerous and surely out of code but I considered lifting all ground and neutral from the panel and making a physical detached separate (from the mains) ground connection near the appliance. It was more an academic "what if" I wasn't foolhardy enough to do it - but I'm curious what the individual sides to ground might measure - would she still be there waiting?

It means you have part of a three phase system. Just two legs of it. If you need 240 volt and you have 240 volt I don't see where the concern is. Typically any machine or appliance that use a 240 volt source and only have a three prong plug use the ground for just a ground and nothing else.

Connect your two power leads of your appliance across the 240 volt feed lines and the ground pin to the common/ground point and don't worry about it.

 

[akuma13]

was considering a step down Xfmer something like this:

Amazon.com: VOD 5000 - HEAVY DUTY 5000 WATTS TRANSFORMER TO BE USED IN 220/240V COUNTRIES WITH 110V EQUIPMENT: Electronics

for the high leg side... any thoughts?

 

[MikeMl]

I just moved into a new building and I'm having some trouble adding a 240v line in for my stackable washer and dryer....

Isn't it as simple as wiring it as shown below:

You just need to make sure that the Drum Motor/Timer bits wind up connected to the Line that has 120V with respect to N. You should be able to tell which terminal at the rear of the Dryer is the one that powers the Drum Motor/Timer. That is the one to hook to the Line that has 120V on it.
The way you hooked it up the first time wasn't it

The other side of the heating element will take care of itself.

 

[akuma13]

Ron,

While I probably can't convince the landlord (without paying for it) to run this separate line - I might be able to get them to swap at the jump point, the line that is currently high leg with the other "missing" hot line. I'm hoping it's as easy as that and there wasn't a specific reason for it in the first place.

P

Br find the source for the panel (likely a transformer if a large facility) and run your machine off what would be phases A and C using the phase center tapped neutral. That would involve a new service line and disconnect. However, given the choice I would use tcmtech's suggestion.
Ron

 

[Reloadron]

Amazon.com: VOD 5000 - HEAVY DUTY 5000 WATTS TRANSFORMER TO BE USED IN 220/240V COUNTRIES WITH 110V EQUIPMENT: Electronics

for the high leg side... any thoughts?

I had one of those when I lived in Italy to power my stuff off their 220 volt mains. The problem is this. You have a 5 KVA transformer with a 2:1 ratio. Thus if ran 208 in you would get 104 out or if you went Line to Line with the 240 you have you would get 120 but I am not sure how that would work out.

However the attached should work. You would use two transformers to do it like the one you linked to. That or find a 240 VAC isolation transformer with a center tapped 120 volt secondary. That is basically what I built in the attached. You can ground it where I show ground on the center tap. I suggest you ground it.

What tcmtech suggested should work? I'll have to look at that more in depth.

This is getting expensive but after you explained the location I understand why you see what you see. I have no clue why they did it that way.

Ron

 

[tcmtech]

I have my suspicions the guy who did the original wiring is unfortunately like far too many electricians who have licenses but not a clue as to how to properly set up a system properly.

You are correct in assuming that only one wire needs to be relocated in the main panel where your service feeds from. Assuming you have a standard 120/240 single phase box in your apartment half of the breaker spaces, what should be the balance of the 120 volt side of a 120/240 system, will be at the 208 volt level in reference to the common line.

Obviously if you have enough basic electrical knowledge to be trouble shooting what you have so far you are likely smart enough to be able to move that line over at the supply point where your power originates from. If its a typical 120/240 three phase distribution panel where it uses what looks like the common style of breakers the phase configuration on the breakers just repeats A B C A B C A B C from the top down so you may get lucky and it could be as simple as moving the main pair of breakers that supply your service up or down one space to properly line up with the correct 120/240 phase instead of the odd 120/208 as you have now.

Some basic poking around with your multimeter will give you the correct set of lines where 120 + 120 = 240 and you still get 120 and 120 from each line to the ground as well.

 

[akuma13]

>> Isn't it as simple as wiring it as shown below:

-----------------
Hi Mike,

It seems so... But I think the majority of the dryer controls run off the 120 side... the gas dryers don't have 240 so they make them this way so they can share common parts and reduce cost... I think the only thing getting the 240v is the heating element and I'd guess it's probably triggered by a relay run by the 120v side.

I can't read schematics very well but I did find these online:

**broken link removed**
**broken link removed**

I can scan a higher res if anyone thinks this would be of any value or help - they are kind of hard to read like this...

 

[MikeMl]

>> Isn't it as simple as wiring it as shown below:

-----------------
Hi Mike,

It seems so... But I think the majority of the dryer controls run off the 120 side... the gas dryers don't have 240 so they make them this way so they can share common parts and reduce cost... I think the only thing getting the 240v is the heating element and I'd guess it's probably triggered by a relay run by the 120v side.

I can't read schematics very well but I did find these online:

**broken link removed**
**broken link removed**

I can scan a higher res if anyone thinks this would be of any value or help - they are kind of hard to read like this...

My reading of the diagram you posted confirms that if there is 120V between N and L2, it wouldn't matter if there was only 108V between N and L1.

 

[akuma13]

update:

Thanks to everyone for the great input and thoughts... Ron's comment "This is getting expensive but after you explained the location I understand why you see what you see." made me think about my approach... this was getting expensive and it was a lot easier to modify the machine than the environment - so I separate it and added a 120v cord.

It was easy enough to separate. The wire placement and colors were opposite of those stated in the schematic but the 2 120v lines are easy to spot - they are the thinner wires.

I thought everything was running fine but by the end of a full cycle it became clear that the dryer motor and the water flush pump in the washer had suffered from the overload and were grinding and malfunctioning - I ordered new ones today.

My revised question is now this: Are there any other areas or parts to consider or keep an eye ion? Parts susceptible to damage from a renegade 208v branch coming though?

thank you!
P

 

[Reloadron]

WE can slice and dice this forever. The problem is I don't see a successful wash load till the voltages are resolved. If it is not possible or practical to find the source to your panel and move a single wire to the correct terminal your options are transformers and that is about as good as it gets. That 208 V leg is the sore point and if you use a 2:1 transformer across that leg and neutral you end up with 104 volts. When we run a motor designed for 120 volts it runs fine. As that voltage is reduced the motor will tend to run hotter and hotter till bad things happen. The same is true for a higher voltage. You could place a single transformer across that 208 leg and neutral and use that side for the heating elements with the good 120 side for the motors. There is also the two transformer config I drew last night. Beyond that I don't see a simple solution. You will be buying a lot of motors and pump motors.

Ron