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Thread: 3 phase questions

  1. #1

    3 phase questions

    So I bought an old elks lodge which I’m turning into my new shop. I recently found out the building has 3 phase power in which I’ve been paying a monthly fee to have. How can I find out what is 3 phase and where’s it is coming I

  2. #2
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    Hi, 3 phase services can have both 3 phase and single phase loads.

    The only 3 phase loads you might have would be motors, air conditioners and large electric heaters.

    You can look at the nameplates and determine whether they are single or 3 phase......Rod

  3. #3
    Most woodworkers would love to have 3 phase in their shops - consider yourself lucky that you have it. Three phase motors are essentially maintenance free and extremely reliable.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  4. #4
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    Quote Originally Posted by Rod Sheridan View Post
    The only 3 phase loads you might have would be motors, air conditioners and large electric heaters.
    This list also may include kitchen equipment in a place like a former lodge.
    --

    The most expensive tool is the one you buy "cheaply" and often...

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    The downside to having 3 phase is that 240V electric heating loads will put out substantially less (roughly 75%) heat when run on 208V. Not likely to be an issue though. And a 240V single phase motor will be drawing more current to compensate for the lower voltage. Many motors are designed to be OK with that though. Pay close attention to voltage drop when you running circuits.

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    In several shops I've worked at that had 3 phase, there was a separate meter and panel for the 3 phase, and then a meter and panel for the 240/140 service. That was the best of both worlds as there was no need to run 240 volt loads on 208. So see if you have multiple meters and panels. A three phase panel will have triple pole breakers.

  7. #7
    Here’s what I know. There are currently like 7-8 air compressors hooked up that are 3 phase motors. Also the heating and AC units are using Big 3 phase squirl cage motors.
    This is all new to me

  8. #8
    Also there’s a big walk in cooler that I plan on turning into a bowl kiln for myself.

  9. #9
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    I agree with the statement that having 3-phase available can be an advantage for your new shop. You might want to consider engaging with your "favorite" licensed electrician to do a walk-through to fully ascertain what you have and how things are setup so you can better plan for changes as you develop your shop plan. A hundred bucks could be well spent money from both the "as built" understanding and also the "what can/should you change" advise you will obtain. You may also want to consider how efficient the old HVAC system is vs replacement with a modern and economic to run MiniSplit system for four season comfort.

    Nice idea for the walk-in...just make sure it has an inside un-latch for safety. Something really old might be wonky.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  10. #10
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    Don't make any assumptions that you will be running 240v single phase loads at 208v. There are several varieties of 3 phase supply. That is just one variation.

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    Quote Originally Posted by Greg R Bradley View Post
    Don't make any assumptions that you will be running 240v single phase loads at 208v. There are several varieties of 3 phase supply. That is just one variation.
    Agreed. There are a few goofy, kludgy 3 phase configurations that have been tried over the ages, but at least around here (Alberta), they haven't been installed for probably 70 or 80 years. Anything that isn't absolutely ancient will be straight 120/208V. You haven't even been able to get a 3 phase delta service of any voltage installed for at least 40 years.

  12. #12
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    Quote Originally Posted by Frank Pratt View Post
    Agreed. There are a few goofy, kludgy 3 phase configurations that have been tried over the ages, but at least around here (Alberta), they haven't been installed for probably 70 or 80 years. Anything that isn't absolutely ancient will be straight 120/208V. You haven't even been able to get a 3 phase delta service of any voltage installed for at least 40 years.
    I've never seen 120/208v Wye in light industrial buildings around here. The norm on strip malls, apartment buildings, etc. where it is almost all 120v loads. Light industrial is 120/240v Delta and heavy industrial is 277/480v Wye.

  13. #13
    Quote Originally Posted by Frank Pratt View Post
    Agreed. There are a few goofy, kludgy 3 phase configurations that have been tried over the ages, but at least around here (Alberta), they haven't been installed for probably 70 or 80 years. Anything that isn't absolutely ancient will be straight 120/208V. You haven't even been able to get a 3 phase delta service of any voltage installed for at least 40 years.
    Ah yes, the high leg. I remember that too well from a shop I worked in college, built originally by the WPA in 1938, roughly 80 years ago as a matter of fact. It had 120/240 delta. Since it was 1938, the hots were all tar-colored rag wire. You had to watch out for that 208 leg.

    Also, since it was an engineering laboratory, and since engineers think they know everything (apologies to any engineers reading this) there were all kinds of uninspected mods done by unlicensed people. I remember one day, the foreman asked me what the ampacity of 3" conduit was. I asked why, and he said because the neutral between the second and 3rd floor was the conduit between the panels. Additionally, at some point I swear they got a deal on green wire, because someone in the 1960s used it for everything, hots, neutrals, and sometimes even grounds. Too bad they didn't use some as a neutral between those two panels.

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    Quote Originally Posted by Greg R Bradley View Post
    I've never seen 120/208v Wye in light industrial buildings around here. The norm on strip malls, apartment buildings, etc. where it is almost all 120v loads. Light industrial is 120/240v Delta and heavy industrial is 277/480v Wye.
    Here it's always 120/240V single phase for residential up to small row housing condos. Small commercial & light industrial is 120/208V 3 phase. Larger commercial & industrial is 347/600V 3 phase. In the 347/600V building there are transformers to handle the 120/208V stuff. 277/480V was phased out of new construction 30 or 40 years ago, but it still exists in lots of older buildings. Most of downtown Calgary (even the new stuff) is 277/480V cause it's all connected to the network distribution system. New industrial building can be supplied with 277/480V at the customer's request, but it is very rare.

  15. Quote Originally Posted by Frank Pratt View Post
    Here it's always 120/240V single phase for residential up to small row housing condos. Small commercial & light industrial is 120/208V 3 phase. Larger commercial & industrial is 347/600V 3 phase. In the 347/600V building there are transformers to handle the 120/208V stuff. 277/480V was phased out of new construction 30 or 40 years ago, but it still exists in lots of older buildings. Most of downtown Calgary (even the new stuff) is 277/480V cause it's all connected to the network distribution system. New industrial building can be supplied with 277/480V at the customer's request, but it is very rare.
    Here in rural Alberta 277/480 is very common. Mostly because about 90% of irrigation equipment is 480v. I installed a 600 to 480 step-down transformer in one place so they could use some second hand equipment that they got a deal on.

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