grab a leg from 208 for 120V pump?

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India34

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a place of worship asked us to install a small pump 6 feet from one of their parking lot light poles, where it's a 208V 20A circuit (actually 196 w V drop at the pole we want to tap into), they don't seem to have a good ground present (I put my meter from each leg to the ground conductor and got no significant voltage other than across the legs) other than from the pole itself being mounted to a concrete stanchion. 208 pumps are out of budget and using a transformer to knock it down to 120 is more work than may be needed. Would taping a leg and finding a way to ground it work with bonding it to the pole or driving a ground rod?
 
No. you probably have 2 conductors for the 208 volts and should have a green EGC bonded to the metal light pole(if it is metal). You can not use the EGC as a conductor. You need a install a neutral to get the 120 volts. This is assuming the 208 volt ckt can have the pump added.
 
Please excuse my first post here and welcome to the Forum. That took me by surprise.

You have already discovered a violation of 250.110 and need to address this if you intend to pull power from said pole. Then your options are to pull a grounded conductor as Bob describes or add the tranny mentioned in your OP.
 
India, welcome to the forum! :)

First of all, you should be measuring a solid 120v between each line and the ground conductor, which should be a solid conductor back to the source, and not depend on a ground rod.

Even then, you can not use a grounding conductor as a grounded circuit conductor, no matter how solid it is. Most of all, you can never use earth grounds as circuit conductors. Never.

The only portion of the existing circuit you should even consider using for the pump is the conduit. If you do, you should include a new, proper equipment-grounding conductor.
 
India34 said:
a place of worship asked us to install a small pump 6 feet from one of their parking lot light poles, where it's a 208V 20A circuit (actually 196 w V drop at the pole we want to tap into), they don't seem to have a good ground present (I put my meter from each leg to the ground conductor and got no significant voltage other than across the legs) other than from the pole itself being mounted to a concrete stanchion. 208 pumps are out of budget and using a transformer to knock it down to 120 is more work than may be needed. Would taping a leg and finding a way to ground it work with bonding it to the pole or driving a ground rod?
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I don't mean to be rude but you need to learn more basic electricity concepts and some of the major rules in article 250 or you are going to kill someone if you do anything with this project. This is everyday type of stuff for pretty much anyone that is an electrician.
 
India34 said:
a place of worship asked us to install a small pump 6 feet from one of their parking lot light poles, where it's a 208V 20A circuit (actually 196 w V drop at the pole we want to tap into), they don't seem to have a good ground present (I put my meter from each leg to the ground conductor and got no significant voltage other than across the legs) other than from the pole itself being mounted to a concrete stanchion. 208 pumps are out of budget and using a transformer to knock it down to 120 is more work than may be needed. Would taping a leg and finding a way to ground it work with bonding it to the pole or driving a ground rod?
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I would be interested in knowing the price difference between a "208" and 120 volt pump on this project. Don't know what the budget is or what kind of pump is needed.

As everyone else said, using the ground as a neutral is not an option.
 
readydave8 said:
I would be interested in knowing the price difference between a "208" and 120 volt pump on this project. Don't know what the budget is or what kind of pump is needed.

As everyone else said, using the ground as a neutral is not an option.
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I'll speculate that the 120v pump can be bought at any home center. Once you get into 208v, you are in a commercial class. And 208v means a three phase service which is most definently a commercial setting. 240v could still be residential grade.

Now if you compare a commercial grade 120v pump vs a 208v version of the same, the price should be very close if not identical.
 
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kwired said:
I don't mean to be rude but you need to learn more basic electricity concepts and some of the major rules in article 250 or you are going to kill someone if you do anything with this project. This is everyday type of stuff for pretty much anyone that is an electrician.
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I will agree with you that this is Electrician 101, but I know from talking to other electricians that these things are not taught the way they should be.

I was lucky that fell in with a great crew when I broke into the trade. Otherwise I might be asking the same question.
 
Somewhat unrelated, but related, I was troubleshooting a gas station where one person working there was a preacher.(theres the somewhat related) He said when he touched the door knob, it put the faith of God in him! Turned out, the door knob was nearly 120 volts to ground! To make a long story shorter, the gas pump contractor used a pvc nipple between the panel and the metal wireway outside, and did not run a ground to it. Even with all of the buried galvanized rigid connected to it, the resistance to ground was still too high to trip the 20 amp breaker feeding the stripped back wire laying in it.
 
Just about a month ago, I walked from a job that was just like this, a neighborhood of condominiums has 120 volt street lighting fed from utility estimated disconnects with two 30 amp fuses, the circuit conductors are #12 thhn/thwn in black plastic irrigation pipe, no EGC's. I was asked to price adding a new 100 watt PS-MH for a sign to the existing system, 1st flag was they didn't want me to notify the utility to add the wattage into the estimated bill, when I saw there was no EGC and that the #12 was undersized not only for the 30 amp fuses and yes one of these fuses was in the neutral, the fact that some of the street light runs were over 1,000 feet. I told the HOA president that the only way I would do this work would be to bring the whole mess up to code or I would not touch it. well as bad as I need work, I walked and never heard from them again.

I don't care, if I discover a danger that can possibly hurt someone, especially children who might be playing around a pole like these, that is where I stop, not having an EGC to protect a pole from being energized is one of the most dangerous installs that was not uncommon to be done, many of the old school who thought just providing a ground rod would be enough, this was one of the most dangerous myths that could have ever been spread around.

I also contacted the inspector for that area to let him know that this was a life safety issue and he has the states blessing to write it up as such, and he ordered the POCO to disconnect the power to those street lights, of course I never was called again, but you know what? it doesn't matter to me, what does matter, is I don't have to worry about reading in the paper of a child being killed because one of those ballast went to ground but the fuse didn't open, and that would be something I would have to live the rest of my life remembering if I didn't do something about it.

Sorry for the rant, but we adults are the only protection many children have, and when we have the knowledge to prevent such a hazard we should do all that we can to prevent this from happening, a dangerous installation such as this is a "Life Safety Hazard" and is addressable in almost all states by law, and a building official has the right to have the power cut when it threatens the life of the public.
 
The comments from others are accurate. Investigate the conduit routing and see if it's possible to pull a neutral conductor to get a L-N voltage at the desired location. Otherwise it is not acceptable to ground a conductor locally and connect it to a leg of the 208V, 3-wire (2L, 1G) branch circuit that's available at that location.
I'm going to focus on the positive and say that it at least shows interest in the trade an a desire to learn that you asked the question instead of just going ahead with an install that would be absolutely unsafe and in violation of basic articles of electrical code. Learning the different between a grounded and grounding conductor is a valuable lesson, but also I think the greater lesson you should take away is that you should spend a load of time studying the code as well as the theory behind it.
 
LarryFine said:
India, welcome to the forum! :)

First of all, you should be measuring a solid 120v between each line and the ground conductor, which should be a solid conductor back to the source, and not depend on a ground rod.

Even then, you can not use a grounding conductor as a grounded circuit conductor, no matter how solid it is. Most of all, you can never use earth grounds as circuit conductors. Never.

The only portion of the existing circuit you should even consider using for the pump is the conduit. If you do, you should include a new, proper equipment-grounding conductor.
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Now Larry I cant believe that you would advise using the conduit as a return path for a 120 volt load??? Please tell me I'm not reading this right?:confused:

If as the OP Say's he has two hots (208 volts) no EGC, no neutral, I see no safe way to use this pole light circuit as a feed for a 120 volt pump.

The fact that he says there is no EGC in its self is a very dangerous situation that should be repaired and advised the person in charge of this church as to the dangers it presents to anyone who can make contact between the earth and this pole if a fault were to occur at this or any of the pole that might be there, it is not uncommon for a ballasted fixture to fault to ground thus making this even more important that this needs addressing.
 
ActionDave said:
I will agree with you that this is Electrician 101, but I know from talking to other electricians that these things are not taught the way they should be.

I was lucky that fell in with a great crew when I broke into the trade. Otherwise I might be asking the same question.
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Sometimes we need to be a little harsh or we get ignored. This is very dangerous situation. How many churches have youth functions and often kids go outside and play. One could touch the energized light pole and be dead in an instant. A small kid was killed not far from where I live a few years ago when contacting an energized well casing - all because someone failed to properly make a connection on the EGC to the well.

This is another good reason for having codes and standards, and enforcing them. Eventually the ones that do not know what they are doing either learn or get forced out of the trade. Hopefully most of them learn.
 
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You all are focusing on the safety (which is important), but would this even work?

Does this pole have constant power or is it fed from a lighting contactor or a switch somewhere? If so, are you okay with only running your pump when the lights are on?

You also said that your 208 is reading 196V. That's already over the standard of a max of 5% and you've not even added additional load.

Can your existing circuit even support the load of the pump...taking into account that the pump needs to start to run?

I think the safest thing here would be to pull in new conductors (mind your derating factors) in the ex. conduit or set a transformer, with suitible taps, to derive your neutral. You'll need to get a grounding conductor out there too, so you might as well forget the tranny and pull in a grounded conductor as well.

We had an inncident here in Columbus here in 2003 where a 9 year old kid got electrocuted after touching a pole on a bridge. :(
 
Often times work at churches is on a tight budget, and many times if professional work appears to be too costly a church volunteer suddenly becomes an expert and can save a lot of money by doing it.

Not only does the OP need to learn the right way to do the installation asked to do, but needs to inform the church trustees, board, council or whatever operations group they have that they have a potential dangerous situation and tell them just exactly what could happen if nothing is done about it. No life is worth saving a few dollars or even a few thousand dollars. To a certain extent the OP has an obligation at the very least to mention that current conditions are dangerous, and if they don't want to do anything about it possibly contacting public health and safety people - at least this would ease my mind that I did what I could to try to remedy the problem and now someone else that has more authority maybe can make something happen.

I don't like to be a tattle-tale but there are some thimes when it is necessary.

I've seen gas suppliers shut off gas service if a safety violation is present, but I can't turn off someone's electricity for similar reasons. POCO's do not get too involved in finding problems on load side of service. You have to do something if you are seriously concerned.
 
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