Electrical wiring in the home shop.

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SteveHGraham
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Re: Electrical wiring in the home shop.

Post by SteveHGraham »

Another thing worthy of mention: a step bit is good for reaming conduit!
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liveaboard
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Re: Electrical wiring in the home shop.

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You Americans would be shocked [hopefully not literally so] to see Euro installations.
220v, 380V all in plastic. Plastic tube with loose wires or multi-wire cables, plastic junction boxes, plastic breaker boxes. Even in industrial shops.

Metal conduit!
Yikes, what a hassle.

You might expect there to be a lot of domestic electrical fires and electrical injuries in the EU compared the the US; could be, I can't find comparable statistics.
Most accidental electrocutions are from contact with overhead or underground lines I'm told.
Fires; don't know.
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Harold_V
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Re: Electrical wiring in the home shop.

Post by Harold_V »

SteveHGraham wrote: Thu Oct 17, 2019 12:09 pm Another thing just occurred to me I could tack the extraneous knockouts with a welder so they can't open and then drill wherever I want.
That offers the opportunity to destroy the device. Not saying that it wouldn't work, but the knockout is generally offset (from the punching operation), so even if you're successful in welding, the resulting surface would be rather irregular due to the offset, to say nothing of the device warping from the welding operation. I'd be inclined to not do it.

H
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SteveHGraham
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Re: Electrical wiring in the home shop.

Post by SteveHGraham »

As long as it's a good sturdy hole, I will not worry.
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Patio
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Re: Electrical wiring in the home shop.

Post by Patio »

Electrical system seem pretty easy on the surface, but are quite complicated in reality. There are a bunch of rules, for everything.

When I was going to school to learn electronics, we had a page worth of electrical formulas to learn. Then the teacher got up before the class one day and says “You can memorize all these formulas, and they are not going to help you in the real world. If you learn the concept of electricity, and stay true to the concept, you can write your own formulas.”

It would be difficult to address each instance of an electrical installation, brought up, in a texted based forum. I can not type fast enough to cover enough ground, or get feedback fast enough, as the discussion progresses, without the process going on for days, if not weeks. The other issue is proper terminology. I have conversations with Harold where it may take a minute for him to figure out what I am talking about, because I am learning all the proper terms of the machinist language. I am not trying to throw you under the bus Steve Graham, but I am going to use your question as an example, and maybe I can help on the way. Case in point of terminology, there is not such things as a “3/4” subpanel hole”. There are 3/4” holes in a subpanel.

I can talk about some concepts, like fill, protection of circuits or devises and am willing to do so. As for specific advise, a phone call would work much better. So PM me and we may be able to connect via the phone. At least I will give it a try. I am not going to publish my phone number on the internet.

With all that said, and again using Steve’s question as an example.

1. ”The people who design electrical panels have some funny ideas. They'll put a whole bunch of 1/2" knockouts on one side, a knockout with multiple diameters on the other side, 15 3/4" knockouts on the bottom...it all appears to be random, and it can cause problems. Sometimes you need a bigger knockout than you have, on a certain side of a box, and because of all the other junk on that side, you can't open an existing knockout up with a step drill, so you're stuck.”

I feel ya! Those panels are generally designed to be installed inside of a wall, so the randomness of the knock out is not an issue, yet the design allow for the most holes of varied sizes in the space available on the tops and bottoms of the panels. Usually on the sides, there are spaces with out any knockouts, that allow one to pick and choose, size and location of the holes. Most panels used in commercial and industrial applications, have no holes at all. This allows the user to create lines of holes for running conduit connections that are easy to secure and it looks nice too.

2. “I need to use a 3/4" subpanel hole to run two #6 wires and a #8 ground. I have Romex in that size. I want to put conduit over it for 8 feet on one side of the workshop, from the subpanel to the trusses, just to protect it from being damaged. The alternative to using the 3/4" hole is to move the #3 feed wires, and that would be major surgery.”

Like others have said, knock out sets are the way to go, but not critical! I have used step drills to enlarge holes, in a particular direction, away from other holes. It takes a lot of physical effort to do so. If the hole does not come out round, or becomes to large for the intended conduit, one can use Reducing Washers, to fix mistakes. Sometime when knocking out a concentric hole, the next larger concentric breaks out too, so you need Reducing Washers.

3. “Can I run 6/2 Romex through 3/4" EMT conduit for 8 feet, with no bends, and adhere to code? I only need one straight 8-foot pipe, on the side of the shop where the panel is. On the other side of the shop, I can use 1" conduit.
If I were using individual wires, the fill level would be something like 25%, but this is big, fat Romex.”

If it fits, yes! Kind of. When calculating fill, individual wires are all that is considered. Romex or other cable type wires are not part of the equation. Cables are two or more wires, contained by an outer sheath. One may run a cable inside of a conduit, for protection of the cable. The ends of the conduit must have bushings to protect the cable from being cut by the conduit. Single wires, must be installed inside of conduit or a wireway. Cables can be used in open framed type structure, as long as the cable it protected up to 8” above grade. Then one is allowed to run them on building stringers, perlins or rafters. 2) #6 and 1) #8 will be create a 25.9% fill in a 3/4” EMT. To calculate fill, take 40% of the cross sectional area of the inside of the conduit vs. the cross section area of the wire type. There are tables that will tell you the cross sectional area of wire and conduits. There are also table that will tell you the are of a particular size of box. Some boxes will have the area stamped on them.

4. “I am not bound by code or permits in this building, but I would like to have safe wiring.
Because there will be no inspection, I can always strip the jacket off 8 feet of Romex and use the individual wires in 3/4" conduit and then a handy box. No one will ever look to see if the wires are marked, and they are definitely ample for the circuit. I would just prefer not to have to install a box 12 feet off the floor in an area where I may want to have drywall in the future.”

Codes are all about personal safety and fire protection. There is a saying, “It does not matter if it is proper or will work, but it must be safe!”

When installing a wiring system, it is best to decide up front, whether one is going to cover the walls or not, as the systems used for each type of installations, are quite different. You may strip the sheath off the Romex and stick it in the conduit, but the sheath must enter the conduit also for a short distance to protect the wires, which defeats the purpose. “Handy boxes” (single gang metal boxes), are not very useful, but to put one wire and one device into. 4 Square boxes, (4”X4”X?”) on the other hand, are quite useful.

With all that said, Steve did not mention what this circuit was going to be used for. The question then becomes, does he have the right wire for the job?

2 wire with a ground, or 3 wire with a ground, or a cable, which is used for which?
One must understand the difference between a ground/bonding wire and a neutral wire, to make this decision.

This is going to be a very simple explanation, to learn more, follow this link.
https://www.ecmweb.com/bonding-amp-grou ... ansformers

A neutral wire serves the purpose of creating a path for the unbalanced current in a system. In the USA where we use two 120V phases to make a 240V system, there will be current flowing on the neutral conductors if there is any imbalance in the system. In a strictly 240V system the balance of the system cancels out any need for a neutral conductor.

An “Equipment bonding system” connects all the metal parts together and creates a low impedance path for ground fault currents. It is there for when things go wrong. If a hot wire makes contact with the bonding system, it will create a path for a lot of current to flow, so much so, that the breaker will trip. And that is the purpose, to trip the breaker.

A good example is a clothes dryer circuit. Old dryer used 3 wires. Two hots and a ground. Now they are all 4 wires. Two hots, a neutral, and a ground.
A dryer is nothing but a 240V heating coil and a mechanism to turn it on and off at the right times, controlling the temperature and duration of drying. The old 3wire dryers had mechanical controls and did not require power for the control systems, only power for the heating element. It only need two hot wires for the 240V and a ground for any fault currents

Modern dryers have all kinds of powered controls systems. Most of these control systems require 120V, which is supplied by one of the 240V lines. This creates and imbalance in the system and the need for a neutral wire. The reason we don’t use the neutral as a ground is because if you put the unbalance current on the ground, any fault current would now need to be the unbalance value, plus the value of the fault, to trip the breaker.

If you get nothing else out of this one, understand this. Never use the neutral wire as a ground!

10 Wheeler Rob wrote “When wiring a sub panel the ground wires and the common must be kept sepperate. And sepperate common and ground run back to the main panel where the common and ground are both connected to the same terminal block. I have seen this not done correctly and results in the ground conducting current back to the main panel.”

And he is absolutely correct!

Liveaboard wrote “You Americans would be shocked [hopefully not literally so] to see Euro installations.
220v, 380V all in plastic. Plastic tube with loose wires or multi-wire cables, plastic junction boxes, plastic breaker boxes. Even in industrial shops.”

Because of the way their system is designed, they don’t use a ground, so you can touch any one wire and not get shocked, but if you touch both, you will feel that. Like any system, there is good and bad to each.

This is a lot of writing for me, and takes considerable time to create. I am not a writer or particularly good with punctuation, so forgive me of my errors. I try. Also it is hard to cover all the angles that should be understood when taking on these endeavors. I can not do that in a text format, but I do hope it will give some insight that you might find useful while you take on your projects. I am on the west coast of the USA and am available to all the members here, in good standing with the board, to chat on the phone, about your particular project. It is the one way I can give back.

Good luck and be safe!
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liveaboard
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Re: Electrical wiring in the home shop.

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Patio wrote: Thu Oct 17, 2019 11:34 pm Liveaboard wrote “You Americans would be shocked [hopefully not literally so] to see Euro installations.
.”

Because of the way their system is designed, they don’t use a ground, so you can touch any one wire and not get shocked, but if you touch both, you will feel that. Like any system, there is good and bad to each.
That is not correct.
The EU systems I've worked on [Netherlands and Portugal, other are the same as far as I know] are 220/240v x3
2 legs make 380 [they call it 400 in the uk]
There is always a ground wire, and if you touch any of those 220V wires, you most definitely get a shock.
Whole system GFI's have been required for more than 40 years. So despite the higher voltage, domestic electrocution is rare.
Nuisance trips however, are common.

Older 3 phase plug / sockets, big + round, are usually 4 pins, 3 hot + ground.
Newer installations mostly 5 pin, 3 hot + neutral + ground.
Although both styles are allowed by code.
Ground rods are installed at each user [like the US], the utility company provides 4 wires to the door. Most users are connected to 2 or them [one hot and the neutral], and their own ground point.
3-phase users connect to all 4.
Since almost nothing uses 2-phase [380v] there is no provision for a 2-phase connection, and no standard plug.

3-phase 380v plugs / sockets come in 3 sizes [16, 32, 64], each available with 4 or 5 pins. just to add to the confusion, there is at least 1 more style, a small square one with flat pins for domestic appliances.
This results in users swapping out plugs a lot, leading to destroyed appliances or gfi tripping when they make mistakes.

Hot is brown or black, with grey as a 3rd color in 3-phase wiring. Neutral is always blue, ground is yellow.

The UK used to use white + black like the US, but switched to EU colors when the joined the EU. I wonder if they'll change back?

I'm not an electrician.
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SteveHGraham
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Re: Electrical wiring in the home shop.

Post by SteveHGraham »

Thanks for the info.

I do not have a neutral because there will never be 125V outlets on this circuit.
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Patio
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Re: Electrical wiring in the home shop.

Post by Patio »

Thank you Liveaboard for correcting my view, and the explanation of the EU system.
When you say whole system GFI, does that mean the main breaker is a GFI type?
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Re: Electrical wiring in the home shop.

Post by Mr Ron »

Thank you Patio for your electrical expertise input. I agree that one should use the correct nomenclature when describing anything. Being an engineer, I subscribe to correct nomenclature, but I guess that is not considered important to non-engineering/technical types.
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SteveHGraham
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Re: Electrical wiring in the home shop.

Post by SteveHGraham »

A 3/4" subpanel hole is a 3/4" hole in a subpanel, in case anyone is wondering what I meant by this confusing term. I'm only a physicist, so I can't be expected to understand technical stuff.
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liveaboard
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Re: Electrical wiring in the home shop.

Post by liveaboard »

Patio wrote: Fri Oct 18, 2019 9:17 am When you say whole system GFI, does that mean the main breaker is a GFI type?
There is a main breaker [or fuse on older boxes] and a gfi in series.
Now that GFI's are cheaper, the norm is to put several in the breaker box, so that the entire house [or whatever] doesn't lose power when one trips.
I have 4 for the domestic 220v circuits, and a few more for the 3-phase users.
I've got underground cables all over the place.

I thought that by now there must be such a thing as an over current circuit breaker / GFI combined, but when I asked at the electrical supply shop they stared at me like I was an alien. Does that exist in the US?

In Portugal the main breaker is adjustable; my main breaker is limited to 22A [x3x380] but if I a higher standing charge, the power company will send someone over to increase it. I think I can go to 40A without any upgrade to the installed wiring.
The monthly charge is rather high here.

Voltage is not as stable as the US. It doesn't jump up and down like in Asia, but a phase will drift up to 240 and down to 210.

I had 205 at one place in Amsterdam, and complained to the power company; they told me 205 is within their norm, which is 230 +- 10% [!?].
That was on a pre-war 220 delta supply. The supply wires to the property were terrifying cloth wrapped little things.
They finally rewired our side of the street a few years ago.
Their "electricians" were unable to comprehend why my permanently moored ship has an isolation transformer [corrosion prevention], and bypassed it.
I had it wired to provide 380v out and they insisted that with a 380v incoming supply it was not needed.
I know how to say 'corrosion' and 'isolation transformer' in Dutch.
As you said, some electricians know some things, others know other things.
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SteveHGraham
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Re: Electrical wiring in the home shop.

Post by SteveHGraham »

A lady just drove up to my house and installed a whole-house surge protector in 2 minutes. What?

I thought they would have to dig up the yard.
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