I’m moving into a new, but temporary shop. Met with the electrician yesterday about the power I’ll need but it reminded me of something I’ve always wondered about. I have machinestools that require 220, 230 and 240 volts. Can anyone tell me what that’s all about. Couldn’t bring myself to ask the electrician.
Don
Replies
I believe 220-240 volts are in effect the same and used interchangeably. This is the same with 110, 115, and 120 volts. Voltage as delivered by the utility company may fluctuate, thus accounting for the discrepancy. The important thing is to separate the 110-120 volts from the 220-240 volts.
Nominal residential voltage in the US is 120/240 (just a convention, actual voltage can be higher or lower). Induction motors built to the NEMA MG-1 standard, which include most induction motors used on saws, planers, etc. are nameplated 115 or 230V or both (among other possible voltages which you didn't ask about). You're probably seeing those non-conforming voltage ratings on older motors. Universal motors don't fall under this standard; just a guess, but I think UL governs there, like toasters. Hope this helps.
Be seeing you...
Some of the motors are older, some aren't. Hmmmm. Everything works so I guess that's all that matters huh? thanks. Don
DonC remember "220, 221 whatever it takes" that is the old joke from Mr. Mom.
The non-conforming nameplate explains a lot of why you are confused. Voltage allowed is + or - 10 to 15 percent by most manufacturers. Warranty or owners manuals will specify this. Motors are effected but electronics really need the tolerance held to the 10 percent factor to be reliable.
In this country it will be within a couple of volts of 240 or 120 most of the time. If you check your power early Monday morning or on a high load AirConditioning day the voltage will be less. The Power company runs the grid and attempts to stay at the spec voltage. Loading on their grid will make the voltage run high or low.
If the problem is consistent then you contact the power company to fix the local transformer or you buy a buck-boost transformer to trim the voltage back into your needs. If it is consistently low then you need to fix the problem as your motors will run hot and destroy the insulation on the windings. Low means 10 to 15 percent low all the time. Shouldn't be a problem you need to worry about.
The nameplate voltages of 220/230/240 are essential the same. These are the manufacturers minimum voltage requirments for the motor. Optimally the power company should be delivering a stable 120v to your primary panel. Two 120v legs and a ground create the 240v circuit. When the nameplate says 220v, the manufacturer is saying that it must have at least 220v to operate within the specifications of the warranty. This manufacturer is attempting to account for any line loss that may be incurred in the wiring from the panel to the equipment.
Thanks for all the comments. Another question:
The electrician wants to run a second 100 amp line directly off the meter to the shop. My other option is for the electric company to run a new line to the shop. It can be done, but there's a lot of nonsense involving this since there is already one meter on the property. The new meter will cost more, but my concern is more about the second line effecting the line to the house with current draws, interference, line noise, etc. The electrician says a second line from the meter will not effect the other line. Anyone know if that is true or not? It's a lot of money to fine out it's bs.
As an after thought and as fair warning, I did a lot work for an electrician and this work I'm getting done was suppose to be my pay back for the work I did for him. Guess what, it's not happening. No more #### for tat trades with anyone in the future. Burn me once, shame on you, burn me twice, shame on me--as the old saying goes.
Don
The electrician wants to run a second 100 amp line directly off the meter to the shop.
I can't quote chapter and verse of the NEC on this, but I don't think it's legal unless the panels are right next to each other, or there is a single disconnect before both panels, or you connect the second panel as a subpanel off the first. You also don't want a long run of unprotected (i.e. no overcurrent protection) service entrance cable to the new panel.
I'd suggest you 1) post this question next door at Breaktime; there's a handful of electricians there who address this type of issue all the time. Post it for your own information, and with this information, 2) go to your local authority (building dept. or whatever), tell them what you are trying to do and ask them what they will accept, pull a permit, and then 3) have your electrician do it to the satisfaction of your local authority. You'll sleep a lot better. Oh yeah, and don't take electrical advise over the internet. Do it by the numbers.
Be seeing you...
Tdkpe,
If I went with the second meter, the meter will have its own drop from the pole. It would be totally separate from the house meter. It would be a second bill, but the second meter at the same address is a lot more cost then the first, and includes all madatory commercial rates and charges along witht the hookup cost.
Don
The meter tap is legitimate. The only concern is that there is a service entrance type breaker on your new 100 Amp service to the shop.
If he's a real electrician then he knows the sizes of wires, disconnects, and grounding required. 100 amps is a lot of juice. That is about 2 or 3 gauge wire depending on the length of the run. I guess you might want to have a sauna, a hot tub and air conditioning out there too. Sounds like my kind of shop.
The electric company drop is expensive with the drop charge, the per month meter/billing charge ( about $12.00/ mo) and it will be a tip off to the tax folks if you are running a business out of there and not reporting it. If you are reporting business income it makes your case stronger. Unless of course you store your boat in the same structure.
Booch,
Yep, he's a real electricain. Permits and all involved for this project. The run from the meter, underground is about 110 feet. He will use underground cable and also put it in conduit. I'm not sure of the guage of wire, but if memory serves me, it was $4 + a foot. Not sure if that included the conduit or just the wire. It did not include labor or trenching charges. Total cost was guesstamated at 2500 to 2700. Air conditioning is a must, but funny you mentioned the hot tub. Some one else was hitting me in the ribs last night with that same thought! lol I wouldn't doubt if she made some calls today on prices!
Don
I'm not certain what part of the country you live in, but $4 a foot is about right for underground conduit, including labor to trench & backfill here in socal.
Instead of adding a second meter, have you checked with the utility planner about upgrading your meter & panel to 200A service, then running a sub panel off of a 100Amp breaker?
If 3 phase is available in your area, use that, if available. 100A 3 phase = 200A single phase. You could pull a 50A 3 phase panel and have the same power as 100A single phase 120/208- this means you can run a smaller gauge wire and save money on conduit & materials.
Here in so cal, a 100' underground run with new 100amp service & panel, single phase would run you about 6-7K total, including grounding.
About your electrical noise concern, just make sure you have adequate grounding and oversize the wire to minimize it. Also ground your equipment to help out. You will still get some noise from the motor brushes, but it will help minimize it.
Edited 9/19/2002 5:02:57 PM ET by craig
2 gauge then. Voltage drop should be minimal.
As for the noise. Spend a couple of bucks and get a surge arrestor and put it in your panel or outside of it. They are easy to use if you have a SqD load center. they just plug in like a 230 volt breaker. it'll cost you 40 clams but it'll lessen the noise and protect from voltage spikes.
As an after thought and as fair warning, I did a lot work for an electrician and this work I'm getting done was suppose to be my pay back for the work I did for him. Guess what, it's not happening.
Don't know where you're located, but in WA state, in King County, electricians have told me "I can't legally do the work for you, but I can stand there and tell you what to do". In effect, they can't 'trade work'. If this is the case in your situation, I wonder why the electrician didn't tell you this up front.
As for the second service - it shouldn't affect your house wiring if it comes off the meter before it enters your house panel. So long as the service drop to your present meter base is heavy enough to handle the combined load. Obviously you'll be running the line from the meter to the shop into a new panel with an appropriate disconnect.
Dennis in Bellevue WA
[email protected]
Don -
I run my shop line from the meter then through a disconnect box, then out to the shop breaker box. The breaker box in the shop is a 100 amp panel. Also installed a separate ground rod for the shop.
Before I did this the shop was on a line from the house breaker box. I noticed once that the main breaker in that box was getting hot. So, I figure I'd better get the shop off the house breaker box ASAP. I had to call the power company to come out and disconnect the meter so I could completed the connections. I reconnected the meter and told them I was done. They came back out in a few days and resealed the meter. I live in an unincorporated area and inspections are not necessary.
PlaneWood by Mike_in_KatyPlaneWood
Thanks Mike and everyone else for the thoughts, suggestions and experiences. I definetely more confident about talking to the electrician with thoughts and suggestions. I'm sure I'm going to hear a lot of, "we can't do that here!" haha
3 phase is pretty strict around here. Has to do with zoning and it's not available in residential or light commercail which I believe here is R2, regardless, I can't have it. If I could, I'd have it in a heartbeat. Lived in Forida in the early 80's in an area where 3 phase had no restrictions. It was great to have. I don't know if it's real or my imagination, but machines seem to run under a lot less load or strain then they do with 1 phase.
---Mike, around here, except for a new initial hook up, the power company doesn't do anything after the poles. If they have to come, figure 400 to 500 hundred an hour min. Because of this, many insurance companies have no deductable when they have to come because of weather related problems. It hasn't been that long since the power companies went to this system, but the phone co.'s started this 20 years ago.
Don
Don -
Here in Texas, and in all the midwest I think, the power company has responsibility up to and including the meter.
Three phase is basically 3 sine waves that are 120 degrees apart. That is as opposed to just one sine wave for single phase current. Less hum for sure.
Household meters are cheap as power meters go. If you run a lot of induction motors at home that don't have capacitors you getting a little bit of free power. Industrial 3 phase meters are much more expensive and read the 'real' amount of power being used. They take into effect the 'power factor angle' which is the amount in degrees that the current sine wave lags the voltage sine wave (or is it vice versa?). The more of an inductive load that you have the greater is the difference between these two angles. Industrial areas will have very large inductive loads. So much so that power companies will install large capacitor banks throughout industrail areas to reduct the power factor angle.
Remember that little tid bit the next time you pay your electric bill!
PlaneWood by Mike_in_KatyPlaneWood
Indeed, Mike, current does lag voltage with an inductive load, but voltage lags current with a capacitive load.
And the difference between single phase and three phase is like the difference between a two cylinder engine and a six cylinder engine. More impulses per revolution does much to smooth out the power flow.
Don ...
Inverters, or whatever they're called, are available for 'creating' 3 phase from regular 220 single phase. Don't ask me for specifics, just that my brother is a machinist and most of his equipment, lathe, Bridgeport, etc., is 3 phase. He ran a line out to his shop and into this inverter thing and has the power he needs. My PM lathe has a 3hp 3 phase motor with a built in inverter.
No idea RE: cost. Worth it or not I wouldn't know.
Dennis in Bellevue WA
[email protected]
I just did this for my shop, here's how I did it.
First, my house was built in 1959 so the electrical system features knob-and-tube, and a whopping 70 amp main service (meter and main disconnect are separate, 2-0 runs to the load center for the house). When we moved into the house, I converted the garage into my shop, at that time I ran 12-3 romex through the shop and installed ganged outlets every 4 feet. In each box there are 2 circuits, 1 to power each receptacle in a two gang box. Both circuits were connected to an existing circuit off the load center. My 230v tool ran off the dryer circuit
I just completed phase 2 of my shop power project. Here's what I did:
1) installed a 200 amp load center next to the meter and main disconnect
2) rerouted power from the meter to the new panel, installed a 200 amp main disconnect (darn thing cost me $150)
3) ran a 2-0 from a 50 amp breaker in the new panel to the main disconnect for the house. Yes, it is redundant, but I didn't want to pull a new line to the existing load center from my new panel, it was a lot easier to reconnect through the existing main disconnect even though it serves no practical function now. Also, it appears that some of the existing stuff was upgraded in the last 10 years, the conduit and wire are all modern... same with the drop from the power pole and the meter. 50 amps is pretty minimal for a house, but we don't have air conditioning and our dryer and oven are gas, so we never overload the panel. It can be upgraded later as I replace the knob and tube.
4) All of my shop outlets now go to the new panel, I have 3 230v circuits with 5 230v only outlets around the shop to match my equipment locations. I also used the new panel to connect all of my outside electrical (lights and such) as well as another 230v circuit from my dust collector, which is located in a shed outside. I also put my shop lights on an separate circuit to ensure I wouldn't be in the dark if I tripped a breaker with a machine/tool.
The net is that I upgraded my electrical capacity significantly without modifying my house load center. In fact, I have taken load off of the house panel in several areas. I have a code compliant main disconnect that is accessible from outside of the house. I also have a modern load center and large capacity breakers, and I can easily add new circuits whenever I need to. I ran 3/4" emt in the shop and that ensures that I can easily pull more wires, and in strategic locations I pulled 10 guage, that ensures I can handle increased amperage if I need to.
As I remodel various rooms and upgrade the electrical along the way, I can add replace my house load center with a new panel and bump the capacity by simply increasing the size of the breaker in the panel I just installed.
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