240 volt switch

I said that wrong. A 4-way switch won't shut off the power.

sorry

I would switch them both off.

Since you say it is temporary, to interrupt the 2 hot legs, you could either use two, regular wall light switches (120VAC, 1 pole), or one 4-way light switch.

I assume its inconvenient to shut it off using the bkr or the pressure switch?

Gary

When you say a 4 way switch, I hope you mean a double pole switch with 4 connection screws, and not a "4-way" labled switch (that looks almost the same) with 4 connection screws.

These are two very diffrent animals!

A double pole switch has two independant paths through the switch and breaks both when you throw it.

A 4-way switch has two paths through the switch that are cross connected when you throw it.

A switch installed as you described will switch the motor, but as has been pointed out, this creates a safety issue. There are circumstances where it is permissable/allowed to protect 220V equipment/tools/machinery in the manner you described. But for the reasons already posted I never do it...Al English

All 240 volt feeds/loads should only be switched with a double pole device rated for or above the voltage and current of the circuit. You can buy a standard style wall switch with two poles to break both 120 volts feeds to the pump at most any electrical supply store or home improvement store. Cost is around $5 to $10 depending upon the ratings and quality but most of these require using a larger size box and cover to fit the switch into. For around $15 to $20, you can buy a complete assembly, box and switch in "Square D" brand. The switch looks just like a standard 240 volt single phase breaker but is **NOT** a current limiting device or short circuit protection device. I don't recall what these are rated for amps wise, you will have to check this to ensure it will handle the loading of the pump motor, as long as the rating is higher than that what you require, you're good to go. These are usually the easiest to install and best choice for the application as you don't have to waste time and effort trying to match different components. The other option is a "disconnect switch". These are a steel box with a pull handle on the side to operate the switch mechanism. I'm not familiar with single phase ones but an unfused 3 pole in this type will run you around $30 to $40. The have a knife blade swicth mechanism and are considerd heavier duty than the breaker looking swicth.

Just a little FYI: Motors are best protected with current limiting fuses and thermal overloads combined in use. Both are sized by voltage and current of the device. Fuses used with motors are generally "time delay" type that allow for the overcurrent loading during motor start-up however, they sometimes will not open fast enough to prevent damage should the motor be running in an overload condition that does not exceed the fuse ratings. For this reason, it is best to install thermal overload protection devices on the load side of the fuses. These allow for start-up current but will open and break the circuit should the motor be in a sustained but limited overload condition. A circuit breaker is designed only for short circuit protection and not for motor overload protection. In most cases, thermal overloads and fuses are not used in residential applications because of the added cost. If you're like me, I have a deep well, 600+ feet with high iron solids, my pump cost me around $1400 to replace (that was for the pump alone). This being the case, it was well worth it for me to install a fuses and overloads at a cost of $150 to protect the pump motor from damage.

I believe your referring to the 4th wire as equipment ground.

The 3rd wire would be the neutral.

T_Bone

In most homes there is only a single service panel, fuse or breaker box. In the "sevice entrance" panel, the first disconnect following the meter, the ground and neutral(common) are connected together and to the ground rod. Beyond this box, ground and neutral must remain separated. Neutral(common) normally the white wire in a 120 volt circuit is a current carrying wire. The hot feeds the device and the current returns via the neutral/common. The ground is a safety wire that should never carry current except in a fault condition.

From your answer, I can see you likely deal with 3 phase a lot since you said "fourth wire". I have the same problem, most of my work is 3 phase 4 or 5 wire. In a single phase, especially residential applications things get nuts. Unlike commercial/industrial wiring where a "white" conductor will always be a neutral/common for 120v and 277v circuits, residential allows this to be a hot as well as a common. 240v feeds are three wire, "black"-hot, "white"-hot "bare/green"- ground. Personally, I don't like romex at all and really don't care for anything that's not in conduit but things are as they are.

Not picking at you here, done it myself many times. he he

This is why I've always stated, wiring by internet is going to kill someone!!!
The poster did not state this was an "old" installtion! Too many assumtions have to be made in order to reply to this post and that is an accident waiting to happen.
And no I'm not upset, just my opinion!

According to NEC, white can only be used for a neutral. All "hot" conductors must be of a color other than white, green or bare wire.

The neutral is the 3rd wire "required" in the circuit.

The bond/equipment ground can be bare wire or green colored and is considered the 4th wire in a 1ph circuit. This is required to keep the case of the equiptment from becoming hot in the event of a short circuit.

If a repair is more than 50% replacement of the total original installation then all of the structure, equipment and utilitys must meet current Building Codes.

NEC does allow for a white colored wire with a "colored taped pigtail" to be used as a hot lead.

NEC goes into extreame detail to make the distinction between a neutral and equipment ground.

Please do not ask me to quote the NEC code refference as I've already looked for my code book, but you know how them wifes are, always hiding my stuff! lol

T_Bone

After re-reading both of my previous posts I do not see, as you suggest, any assumptions made on my part. In fact, I advised Bob not to switch the motor in the manner he asked about. How is that statement a contribution to "an accident waiting to happen"?

The neutral 3rd wire is not, as you stated, "required" for a 220V device to operate. However, if the unit also needs 110V power, the neutral is required. In either case that neutral is grounded by the utility supply. For many years 220V 1ph cooking stoves, clothes dryers, small welders(something you should be familiar with), and other devices, had a three prong plug. Two of these prongs were "hot", and the third was the neutral/ground. These devices utilized the neutral for a ground, with no additional/redundant 4th wire grounding. A number of years ago this changed, and current models of these products have provisions for an additional equipment ground(green) that is to be grounded on site. This 4th wire ground is typically accomplished via a 4-prong plug. The requirement for a 4th wire/redundant ground came about as a result of concerns that the utility company neutral could become disconnected, or energized by contact with a "hot" power leg. It is my experience that municipalities do not require upgrading of existing 3-wire 220V installations to include the 4th wire "safety" ground. Less than 6 months ago I installed a new cooking range and clothes dryer. Both of these appliances were configured to use, or not use, a 4th wire ground. If the 4th wire is not used/available, the neutral serves, as was traditionally the case, to ground the device. While having the additional 4th wire ground is preferable, there are millions of neutral grounded devices still in use. That being the case I resent your assertion that Mark and/or I, are providing bad advice that is "going to kill someone"...Al English

Both you and Mark give excellant advice and have been for along time. I was tired and was trying to cover three posts with one answer, my intent. As you can see I left cubub completely out and had to make amends.

This is my point. It takes more than just a simple answer to make sure the poster understands what and why there idea is a bad idea. With the information given, I don't know if he's working with a newer installation or an older installation. By the information asked, it's apparent the poster has a limited knowledge about basic electricial theory and that is my refferance to " someone is gonna get killed with wiring by internet" and "an accident waiting to happen". Any information posted about his question could be just enough info to get someone hurt as it would take books written on the subject for someone to fully understand, "why not".

In the past 35yrs, I have never worked on a 230V circuit where a neutral was not required.

The NEC went to a 3wire 115v circuit for protection of the neutral. The hot lead is protected by the fuse or breaker. If a 2 wire 115v circuit neutral became open then someone was at risk of being "electrified". With the 3 wire 115v circuit if the neutral becomes inorperative for whatever reason, then the 3rd wire, the equipment ground, will keep the circuit grounded so no harm will come to the user.

At the same time NEC implemented the 3wire 115V circuit requirement, NEC also required a polarized receptacle and cord cap. This was to keep the outside of 2wire appliances from becoming "hot" to the user. In the old 2 wire 115v non-ploarized circuits, depending on which way the cord cap was inserted into the receptacle, current could be applied to the outside of the appliance and the user could become a better ground than the appliance and get electrocuted, which they did on a regular basis.

NEC then applied the same neutral/grounding method to 230v circuits. Along with this scheame, NEC also required a fused equipment disconect with-in sight of the equipment. I really liked this one as it kept me from having to climb off roofs when working on refrigeration equipment to shut the breaker off/on.

T_Bone

Bob, the original poster on this topic, I want you to know that nothing I am going to say below is directed at you, or anyone else in particular.

Every so often I am faced with a situation where a person is talking about repairing their brakes or steering, wiring a house, running a chainsaw, shooting a gun, or some other activity that places a high cost on not doing things right. In the situations I am talking about it is obvious from the remarks being made, or questions being asked, that the person has little or no concept of what they are getting involved in. Unfortunately I have found that simply telling someone they lack the knowledge to do something seldom causes them to rethink their plans. After all, the less one knows about something, the easier it looks. Knowing they are likely going to proceed anyway, I include with my cautions as much help and advice as they are likely to understand and remember. Sometimes a little detailed advice can serve to illustrate at least some of the realities and dangers of the undertaking. One of the problems with forums like this is that bad advice is afforded the same exposure and credibility as expert advice. And, people will often ask the same question until they get the answer they wanted to hear. As you pointed out TBone, becoming an electrician is not something that can be achieved by reading this forum. But all things considered I think it's better that a person gets some guidance from someone like you, than to proceed with no clue at all...Al English

You brought up a good point. Maybe the forum could have a post each week where everyone chips in and explains a indeapth how too project with each person taking a different segment of the topic where the last one left off.

Maybe along the layout in one thread:
1) Define the topic to be discussed
2) List the topic segments of the discussion 3) Each person would then write about that segment

Anyone could start a topic and define the segments. Anyone could agree to write about that segement or maybe it would take a team to cover a topic segment.

After all the topic segments were spoken for, then start a new thread of the topic with each person following in order. Comments and questions then could be made under each segment.

I can see where this might work out and be some fun and I will learn something.

I've always hated turning someone away that has asked a question just because the answer was very long and drawn out.

I'm a very poor typist and it takes me forever to post something.

What do you all think? Would it work?

T_Bone

A service like that would be great. But unless I am missing something I don't see it eliminating the incorrect and incomplete advice, oversights, and differences of opinion, you are concerned about. Besides, it's a lot easier to let you answer the questions while I just jump in once in a while and stir things up...Al English

My work is wide based. Since I build custom machinery as well as repair and modify existing machinery, I needed to have a working knowledge of many fields including electrical. Because a lot of my work is done in the mines, quarries and manufacturing areas, I am most familiar with heavy duty side of wiring. After reading T_Bone's post about working on HVAC units, I see that he is also more familiar with industrial/commercial wiring as well. Most of the work I do is in areas where water/moisture and corrosion is a major concern and is taken into account especially when doing wiring. Many items not only require a ground but redundant grounds to provide an extra margin of safety for the operators. An additional concern is lightning strikes since most of this equipment is in metal structures in the middle of open plateaus making them an excellent target for lightning. Where as most buildings and equipment have a single ground point, some of these may be grounded every 20 feet around the perimeter. The same goes for the equipment, some pieces may have more than 4 ground connections. Floating items such as shaker deck separators sitting on rubber air springs are electrically isolated, these will often have at least four ground points to the base frame using braided straps or fine strand copper cable.

The use of full size or over sized grounds is also very common. Say a machine calls for a circuit fused at 175 amps but is being fed from a 400 amp panel, 4/0 power feeds are pulled and the ground conductor must also be a minimum of 4/0 as well however, in some cases, a ground conductor sized at 350-500mcm will be used for this circuit to allow for the additional current capasity should a major failure occur. This is done because the circuit has the potential to become energized with up to 400 amps from the feed panel until the main fuse or breaker opens stopping the current flow. Working in these environments plays a major roll in wiring especially the grounding. The NEC may only require a single ground conductor sized at 60% of the circuit capastity (example for discussion only) but conditions of the installation may indicate using a ground conductor 5 times the size of the normal current carrying feed conductors. There are concens in these multi-ground operations since the possibilities for problems are infinite. It is nearly impossible to maintain isolation between equipment safety grounding and lightning strike grounding and because of this the entire electrical system undergoes careful inspection at least once a month to ensure that all grounds are secure and operational.

All eletrical connections can come loose over time and this is likely my biggest gripe with all applications, lack of inspections following installation. Most people do not think about this until there is a problem especially in commercial systems. I'd say at least 50% of the electrical breakdown calls I have had in plants in the last 10 years were caused by loose connections. About two years ago, a neighbor asked me why she got a shock when she touched the outside water spigot when not wearing shoes. A quick look in the service entrance panel revealed the cause. The ground had corroded off the terminal and there was no connection at all. Checking the whole service, I found that the only reason the service wasn't lost was because the drop line from the can on the pole also fed the house next door. This house was grounding through triplex to the other houses ground rod. She got shocked simply because she had a lower resitance than the ground circuit. I contacted the utility and had the service shut down to make the repairs. Checking the rest of the connections, every single one of them was loose including the main power feeds from the meter base to the main breaker, not just a little, one to two full turns on most of screws were needed.

One more gripe and I'm done for today. I see all sorts of instructions on electric devices stating "connect ground lead to copper water pipe". Fine and dandy if the copper pipe goes to the well or city water system that uses all metal pipe. Unfortunately, most of the piping now days is plastic. I have a well with a submersible pump. When installed, the pump was wired with twin lead AWG12, no ground conductor at all. The pump is connected to the water system with ABS tubing. I suppose, the ground was not considered assuming if it shorted, the current would pass through the water and cause the circuit to open under a short condition. Since the steel well casing is not connected to the water copper pipes except for the water in it, this is a really poor ground. Now, following the instructions could lead to a device energizing the water system in the home. Like most people, I never thought about this until the pump crapped out. Now, the pump is wired with three AWG10 wires, 2 hots and a ground and the well casing is connected to the copper water pipe with an additional piece of 4/0 copper wire.

Safety first and foremost in everything.

I know what you're saying and fully agree with it but sadly, it is not followed much, if at all, in residential applications. If you would see some of the crap I come across in industrial applications, it would scare the heck out of you. I've seen disconnect panels double fed from other locations, seriously overloaded panels and circuits, circuits without grounds, circuits using the conduit as the neutral (ran into that one in my own shop from the guy who was here before me...found that one the hard way too...)

My cousin put up some modular rental homes two years ago. Total electric and every single 240v circuit uses standard three wire romex, black - white - bare. To top this off, both homes came with aluminum wire to the range and dryer outlets. I haven't read a current NEC book lately but isn't this a no no too? I fought the utility company on their using 500mcm AL for my underground 3 phase feed. I took me calling the main office and arguing the point with the head engineer. This is a 240' run in conduit, I did not want to chance anything, after two hours on the phone, they finally agreed to run 500mcm Cu. Granted, I don't have that many big current draws but running full load in the shop comes to around 200 amps at any given time, factoring in ambient temp swings from below zero to over 100F, that leaves a lot room for expansion and contraction problems loosening connections with AL wire and Cu terminals.

I can't argue your point about safety but you know how the all mighty dollar fast out weighs any concerns about someone getting killed or injured. I'm still in the process of re-wiring my entire shop but when I found the first problem, I shut the whole system down and checked everything. I ended up running some temporary feeds to keep working till I get all the conduit and wiring in but at least they are safer than what was here.

Well my code book if I ever find it is 12yrs old to boot. I'll pickup something else 6mths from now and put it back where it should be now :)

You won't believe some of the nightmares that I've seen here. I've been called out where the last "electrical wizard" decided to jump all the safety controls out of a 50 Ton refer, tore off the schematics and the owner wants to know why it's going to take 12hrs to rewire the unit.

One idiot cut 1/4" x 1/2" flat bar to replace the fuses he burnt out after wiring the unit backwards. I never could figure out how he installed them without killing himself as he came back and did more work after installing them.

Another one ran 460v feeds accross the roof without any conduit.

Ya the last time I looked AL was allowed with special connectors and goop. I think MH had a more restricktive use tho. Been to long ago on that one.

T_Bone

I wasn't ignoring you, I just couldn't remember your name and I like to address people by there name/handle when replying. If I would have to back out of my writting I would have lost what I had written.

Please see my post to Mark and Al.

T_Bone

Until a few years ago, on many 220V devices, the neutral could be used as the equipment ground. No 4th wire equipment ground was required. Your statement describes current practice, but not necessarily an older installation...Al English