Wiring a single pole switch into a 220v circuit
 

Im in the process of wireing a 50X100' shop. I have a 220v circuit that runs from the circuit box across the shop to a small 6 gallon hot water heater. It is wired with two hot wires (red and black) and a green grnd wire. I would like to pick up this circuit on the far side of the shop and also make it available to energize a 220v receptacle which I can use for my 40 amp welder. To be certain that the hot water heater does not kick on while Im using the welder, I would like to interupt the circuit to the water heater with a a single pole switch. Is this a dumb thing to do and if not, how does one wire a 220v single pole switch to make this work?

Also, I hired an electrician to hang and wire halogen lights in the shop using 22Ov circuits. I wanted the shop wired in three zones so I wouldnt have to have all the lights on at the same time. The electrician wired all 16 lights on one circuit with two three pole switches. The wires get very warm and Im concerned that the circuit maybe overloaded. Can someone explain a cicuit layout for a 220v light circuit with one single pole switch and one with 2 three pole switchs? My building is steel and I have been running all circuits in 3/4 inch conduit.

ONe last question - When one wires a 220v circuit by connecting each hot wire to it own 20 amp circuit breaker, is the circuit considered a 20 amp or 40 amp circuit. When connecting the hot wires, one to each pole on double pole 40 amp circuit breaker is this considered a 220v 40 amp circuit?

before I start this comment the shop size is almost the same size my is 30X70 feet with 16 ft ceiling. ( the only diffrence is the voltage I have 480 volt system in there [ it is zoned as commercal ])

Now let get to the topic here.

The small 6 gallon waterheater typically are 1500 watts range and it will useally come either 120 volt{most common for 6 gallon } or 240 volt verison and I suggest that you run this waterheater on it own circuit for codewise and also put a local disconnect switch ( single pole HD toggle switch for 120 v circuits or double pole toggle switch for 240 volt circuit or A/C pullout switch will meet this requirement )

{ side note I will not add the waterheater to the welder circuit for safety reason }


What wattage the luminaire you will be using and for myself I will useally stay away from halogens I know they will light up shop ok but they are power hog.

And how high is your ceiling is ??

Typically I used either 250 w or 400 w PSMH { pulse start Metal Halide } luminare and for 240 volt circuit you will limited to 9 { 400's watter} max otherwise you will have issue with the 20 amp circuit or use the flourscent luminaire may be better suited for your shop depending on the ceiling height.

Yes you can run the luminaries in sections by using the three way switches but a trick is add a contractor { magatic switch } check with your electrician to see if he like the idea { you may understand why i rather go this route if you want the three way functions }


a 20 amp breaker is 20 amp circuit and 40 amp breaker is a 40 amp circuit.

they are not addtive at all.,, so if you have two pole breakers it will stay the same as single pole breaker so like 20 amp on one pole and 20 amp on other pole it will stay 20 amp.

the other tip for ya is make sure you bring plenty 120 volt circuit for receptale and do plan this ahead so it will be much easier down the road when ya get this all hook up.


If ya have more question just Holler we will help ya

Merci,Marc


Here what typical low/high bay flourscent luminaire look like http://www.alumen-8.com/images/fixtu...el8w246hue.jpg



this what low bay HID look like http://www.ruudlighting.com/images/i...ial_series.jpg

wiring a 240V single pole switch
 

Marc, Thanks for responding so quickly. My shop has 16 foot eves and the ridge is approximately 20.5 feet high. I am using metal Halide HID luminaires. I have three different kinds of fixtures.

2 each low bay fixtures that are wired for 120v at 400Watts The only amperage I can find on these two fixtures is 1.0 amp at 480v. I would assume that 120v amperage is probably 4amp.

8 each high bay 250 watt fixtures that maybe wired at at 120/208/240/277V The amperage is 2.6/1.5/1.3/1.2 respectively.

both of these fixtures maybe hung in damp locations and are rated at 55 degrees C. None of the above fixtures have been hung.

The 16 fixtures that have been hung are Cooper lights rated and 90 degrees C. They are 400 watt fixtures and are wired/hung at 240V/2 amps. They can be wired for 120V at 4 amps.

Correction on the water heater its a 30 gallon water heater wired at 240v on a 40 amp circuit. Im guessing that it has two elements in it as there is an upper lower and total rating of 3800/2855 which I think must be amperage usage of each element. I have 3 each 240V HD single pole switches. Will one of these work for a local disconnet on the water heater?

I understand you to say that it is not safe to use the hot water circuit jointly for my welder which I conclude means run a new circuit for the welder alone. My electrician pulled number 10 wire for all of the 40 amp circuits. Is this the correct size of wire. He has left the area but after hearing numerous complaints from a number of his customers after I used him, Im not confident that I can trust what he did in my shop.

2A * 16 fixtures = 32A. #10 wire is rated for 30A... Moving the lights to 3 separate switches / circuits is a good plan.

40A circuits should be run with #8 wire.

Also, I believe that welders (depending upon the type) require a heavier gauge of wire than regular branch circuits (NEC 630). Probably an electrician will jump in here with specifics.. I'm not 100% clear on the requirement.

I'm not sure if a water heater is considered a continuous or non-continuous load. If it's continuous, you would have to put it on a separate circuit (or upgrade the circuit for 90A).

A single pole switch wired to either hot lead going to your HW heater would turn it off when opened, however I it's code (and safer) that you use a double pole switch. The switch would have to carry the same rating as the circuit (40A). But your wiring should be upgraded on that circuit to #8 to match the breaker and load of the HW heater.

Thanks Scott, I was afraid you were going to say the 40 amp circuits needs to be run on a no. 8 wire. Thats probably why the wires for my light circuit get so warm. If #8 wire is what I need for a 40 amp circuit, then #10 must be for a 30 amp and #12 must be for a 20 amp and #14 must be for a 15amp. Using a single pole switch for a 220 amp circuit allows me to interrupt the circuit on only one of the hot wires. I havent looked at a two pole switch but I assume that a two pole will allow me to interrupt both hot leads on a 220 circuit. I should have been able to figure that out but I wasnt able to find any HD 2 pole switches at home depot or Lowes. Just single and three pole. Based on your input it looks like Im going to have to rewire my lights to work on three or four zones and keep the amperage down below 30 amps a circuit. especially if Im going to add the other 10 lights. I probably ought to shoot my electrician while I am at it!

Yep. (Assuming the wire runs are not overly long -- the longer the run the more the resistance of the wire, the larger the voltage drop at the end. I think you're probably OK unless the wire snakes all over your ceiling from light to light.. And putting the lights on 3 circuits only makes you better off there, too).

Yep. But it's not safe b/c the switch can be open but there's still a hot lead going to the device/receptacle/whatever.. It can lead to the assumption that the power is off completely. Note that it wouldn't work on a 4-wire appliance, because something in the appliance can still be powered from the non-switched hot -> neutral.

That's right. I don't know if Lowes or HD would have a 30 or 40A double pole, but I'm surprised they didn't have 15 or 20A. Leviton (and others) make a wide range though, and you can definitely find 'em online or at an electrical supply house.

Or at least make him fix it??

Half the lights are as much as 100 to 1050 feet from the Circuit box. What is considered an overly long run. Im now thinking of converting all the lighting to 120V and putting no more than 6 lights on each circuit setting them up on 30 amp circuits. The most amperage I would carry on any one light circuit would be 24 amps. That means I would have to go to at least four zones and probably 5 if I put as many lights as I want hung in the shop.

I'm guessing that's "100 to 150", right? :)

Depends on the load applied to the circuit; but like I said, probably not an issue if you're separating the lights to different circuits. Right now you're running over capacity, so I guess 1 ft is too long. :) Any sarcasm aside, I'm not really sure how to derate your wires properly -- I'm not a pro electrician, but maybe one can jump in here?

Sounds reasonable.. If 4-5 zones is too many, you can always keep one or 2 circuits @ 240V to accommodate more fixtures @ 30A. I guess you want to cut back to 120V so you don't need double pole breakers and switches? Save panel space and $? Can't argue with that..

I really strongly do not go this route with 120 v 30 amp circuit the code is pretty spefic on this one

espcally true with HID's { belive me I done this all the time with large commercal / Industrail complexs }

you will end up using more wires and circuits for genral lighting circuit at 120 v than what you can do on 240 volt circuits.


I will give you a example how I dealt with this and been sucessfull with alot of my customers

If this building do have service doors on both end all you need just one circuit that wired for 3 way's that circuit you can used with flourscent luminaire something like over workbench or in few spots where you can able turn them on pretty fast instead of waiting quite few minutes for the HIDs to warm up { you know how long to get them back on when someone say opps hit wrong switch :huh::whistling2:}

For the HID's just a standard double pole toggle switch will do the task or otherwise you can use the breaker as switch due most breaker manufacters do allready listed them as switching duty but somecase will marked HID breaker { if you going to use them as switching }
Otherwise doublepole switch will do the task for reasonable set up so you can able turn on the luminaires as need to.

You can have them in 3 or 4 sections depending on the layout.

Mine shop have 4 circuit for the HID's due I can able finetune as I needed to { plus they are HI/Low set up as well }

Now next step I am glad you speak up about the waterheater with 30 gallon size for 3800 watt element typically can use #10 wire with either 25 or 30 amp breaker. Do not use the single pole switch on the 240 volt waterheater for safety reason due when you turn off the switch all you are doing is disconnect one leg and other leg is still alive and if you work on it. in worst case senicero., someone will get hurt pretty bad or kill from this. that why a double pole switch or nonfused disconnect switch or A/C pullout disconnection device.
All three items I mention are approved methold to safety disconnect the power in correct and safe codewise with it.


It is correct as long you have multi tap ballast yes it can be switchable but if only single voltage you may want to open up the ballast housing to verify if that is a single voltage ballast or see the numbers of lead { wires } comming out of the luminaires they will marked " COM " common 120, 208, 240, 277 somecase you will see the 5th one is 480 volts.
The latter two { 277 and 480 } is useally resvered for commercal / industrail electrical system.

If you verify it and it is a single voltage ballast there is two choice you can do is change the ballast or get new luminaire.

The other thing you have to be aware with the 400 watt luminaire that if it wired for 120 volts you are only allowed 4 on 20 amp circuit.

If have more questions just holler here

Merci,Marc

Marc, I'm sure you are right, but I just want to know for my own benefit why 120V with HIDs is wrong in this case? I mean, providing that rlmorgan wants to divide the lights onto different circuits. I see your logic, obviously 240V would allow 2x as many lights as 120V for the same Amps, but if he wants less than half as many lights per circuit anyway, what's the harm in 120V?

ScottR.,,

There is noting wrong to run the HID's on 120v circuit but it depending on the wattage of the luminarie and keep in your mind if this building have all 400 w MH's and they draw 4 amp each at 120 volts

Like example I know 60X60 building with 22 ft ceiling that took in total of 30 - 400 w MH's and this building did have wired for 120 volts result of 10 circuit set up { the customer want little more finetune control } really 8 circuit will serve just fine most case but with 8 circuit you can see why the numbers of wires it have to be pulled thruout the building set up.

IIRC it used about 800ish feet of #12's THHN/THWN

Now try this with 240 volt the amout of circuits drop down to 5 circuit and the amout of wire and conduit drop down a bit more like 500ish feet

You can see why with very large building normally I will wire up the HID and flourscent luminaire on highest voltage if they have.

In case if you ever see in some of big box store and wally world luminaires ?? they are wired on 277 volts so they have more luminarie per circuit that will add up saving pretty fast.

Merci,Marc

Thanks Marc! I think we're on the same page.. :thumbup:

Thanks to both Marc and Scott,
I see Marc's point about saving costs if I stay with 30 amp 240 volt circuits. One thing for certain, I will be able to use the #10 wire that has already been pulled and by using a 240V circuit I can add more lights in areas where I may need more than 6 HID lights. A 30 amp 240V circuit would let me put as many 12 HID lights on one circuit. 2amps X 12 = 24 amps. I might be able to go one more light but no sense pushing the limit any more than that. I plan to use 1/3 of the shop for wood working so I would like to have as much light in that quadrant of the shop as I can get. Old eyes if you know what I mean. Very glad to hear that the #10 wire running to the water heater is ok and I will be sure to use a Two pole switch for the diconnect.

I also understand what you mean when your talking about waiting for the HIDs to come on and have been running 120v circuits and hanging flourescent lights over my work benches. I think that should keep my electric costs down when Im only working at the bench. No need to light the whole shop.

Thanks also for the discussion on the Low Bay lights, I will see if I can convert them to 240 volts. If I have questions after I pop them open, I'll put the questions to you guys in this forum.

After our discussions Ive decided to pull #8 wire for my welder receptacles. Starting that circuit at the circuit box located in center of the shop should keep the run to each receptacle at no more than 85 feet.

Marc, I dont follow what you are saying with this comments "IIRC it used about 800ish feet of #12's THHN/THWN" . An I dont understand what a Hi/Low set up is. Would you provide futhrer clarification of these comments please?

Again thanks to both of you for all the help.

Sincerely
Rick

Scott, Id love to make my electrician help me fix these light circuits but he moved about 900 miles west. I think he got out when the getting was good!

Rick, no prob, glad to help!

Just wanted to clarify.. without looking back at the post, I think you said you have a 40A breaker on the water heater circuit? If so, you should downgrade it to 30A. The WH draws < 30A, so you should be OK with that.

BTW - Very jealous of your shop. I'm moving up from no shop to a 1-car garage, so I guess I'm going in the right direction.. Ah well, c'est la vie. :wink: