I have a quick electrical question that I was hoping to get some opinions on. I have two 220v 20amp lines that I need to make longer due to having to rearrange my shop. They are for my Delta UniSaw and my 3HP Grizzly Shaper. The wire is currently 12/2 each with its own 20 amp double pole breaker. My question is would it damage my equipment or cause any significant voltage loss if I were to splice those lines to make them longer? The situation is that we can't pull new (longer) wires right now. Might be able to in the future. But for now I will have to splice them. Local code is not an issue, I just want to know if this will cause any issues with my machines?
Did you consider making your own extension cord using portable power cord you get in home centers? This way you can always use the extension cord for other purpose.
You can use more 12/2 wire to make those runs longer if you need to. You will need to make that connection inside a junction box that is accessible in the future. Be sure to use wire nuts suitable for that size wire.
"Local code is not an issue" is a terrible, horrible, no good, very bad reason to do substandard electrical work.
As mentioned, splicing is okay if done in an accessible junction box. Longer is okay, if ….
I believe code has limits on how long a run can be for a given circuit rating (15 A, 20 A etc) for a given wire size. You can look that up. So there will be some max length for a #12, 20 A run. Some loads will draw MORE current as the voltage goes lower (not everything behaves like a resistor). I assume this is why code is concerned with this.
I'm pretty sure code always applies in the USA. I believe each state enforces the NEC with a few of there own local modifications. But even if you don't legally need to do it, the code exists to ensure a safe installation. Sure there will always be situations where some code restriction isn't making it safer. But unless you're an expert, it's always best to stick with the code which has been developed by experts over many decades.
I also doubt it is code to extend a circuit with anything other than the same wire size. This would run the risk of fooling someone into thinking the whole circuit was at the larger wire size.
You didn't mention how much longer you want to make the wires, but here's an example to give you an idea what will happen.
Assume you add 100 feet. That creates 200 feet, round trip of wire. #12 wire is about 1.7 mOhms per foot.
total added resistance = 1.7 mOhms/ft x 200 ft = 0.34 ohms of resistance.
Volts = ohms amps
For the added voltage drop of 100 feet at the maximum 20 A circuit current.
volts = 0.34 ohms 20 Amps = 6.8 V
This is on a 240 V circuit so represents 2.8% decrease in voltage at maximum current.
Of course, you won't be operating at max current of 20 A or likely even near it except when a motor starts. So would this matter, I have no idea. Though I doubt it would be noticeable in most cases.
There is no set length limit of a circuit in the NEC. Calculated loads and distance set the conductor size and length limit. Two different wire sizes can be used in a circuit but the over current protection must be set to the smallest conductor size in the circuit.
The lines just need to be 10ft longer. I will use the same wire size, 12/2, and make the splices inside of a junction box. Thanks for the help fellows!
This was a question I had (enforced by states, and which ones) so Google is your friend. What I found was that there are 3 (AZ, MO, MS) states that haven't adopted the code, and the others have adopted different versions. I know where I'm (my local) at (Ohio) there is no active enforcement unless it's at the municipal level. In fact, a small village that supplied power to my last house knowingly allowed violations of the code in some structures they serviced. I thought this was kinda interesting, especially since I didn't think I was subject to the code at all.
I m pretty sure code always applies in the USA. I believe each state enforces the NEC with a few of there own local modifications.
- clin
This was a question I had (enforced by states, and which ones) so Google is your friend. What I found was that there are 3 (AZ, MO, MS) states that haven t adopted the code, and the others have adopted different versions. I know where I m (my local) at (Ohio) there is no active enforcement unless it s at the municipal level. In fact, a small village that supplied power to my last house knowingly allowed violations of the code in some structures they serviced. I thought this was kinda interesting, especially since I didn t think I was subject to the code at all.
LoL, I have had a similar experience with regard to code. I live in a small town in the rural south, and our local electrical inspector is my next door neighbor. In my previous shop, which was a commercial shop, we had to run some new lines for outlets at various machines. I was just starting my business and already had the wire but no conduit. It was a pole barn style shop with open walls. Well I ended up running the wires with no conduit, which is technically against code in a commercial shop in my state. I had my neighbor, the electrical inspector, come look at it, and he said, "looks good to me".
This would be the same insurance company which made me get rid of diving board and slide on swimming pool to avoid cancellation of my homeowner's insurance? The board and slide had only been in use for thirty-five years. They wouldn't even let us keep them if we signed a waiver of liability related to pool and equipment.
As mentioned, splicing is okay if done in an accessible junction box. Longer is okay, if ….
I believe code has limits on how long a run can be for a given circuit rating (15 A, 20 A etc) for a given wire size. You can look that up. So there will be some max length for a #12, 20 A run. Some loads will draw MORE current as the voltage goes lower (not everything behaves like a resistor). I assume this is why code is concerned with this.
I m pretty sure code always applies in the USA. I believe each state enforces the NEC with a few of there own local modifications. But even if you don t legally need to do it, the code exists to ensure a safe installation. Sure there will always be situations where some code restriction isn t making it safer. But unless you re an expert, it s always best to stick with the code which has been developed by experts over many decades.
I also doubt it is code to extend a circuit with anything other than the same wire size. This would run the risk of fooling someone into thinking the whole circuit was at the larger wire size.
You didn t mention how much longer you want to make the wires, but here s an example to give you an idea what will happen.
Assume you add 100 feet. That creates 200 feet, round trip of wire. #12 wire is about 1.7 mOhms per foot.
total added resistance = 1.7 mOhms/ft x 200 ft = 0.34 ohms of resistance.
Volts = ohms amps
For the added voltage drop of 100 feet at the maximum 20 A circuit current.
volts = 0.34 ohms 20 Amps = 6.8 V
This is on a 240 V circuit so represents 2.8% decrease in voltage at maximum current.
Of course, you won t be operating at max current of 20 A or likely even near it except when a motor starts. So would this matter, I have no idea. Though I doubt it would be noticeable in most cases.
Ok so I have one more quick question for anyone with electrician experience or knowledge. I would like to take a 12/2 20a line from my breaker box, and have it split into two 20a lines next to my machines where I originally intended for the splice to be located. That way I end up with two 20a recepticals, but, only one machine will be used at a time. Never two, on this circuit.
I was told to wire this up inside of a junction or gang box, and to use wire nuts, connecting each red wire, each black wire and each ground wire together. Is this the proper way to take a single 20a line from my breaker box, and have it split into two 20amp lines that could then go to two different machines? (Again, only one machine will be used at a time). The run from the breaker box to the junction point is roughly 20' and then it will split into two runs that are only 10' in length each.
That is one acceptable way to do it. There is no red wire in 12/2, just black, white, and ground. You'll wire nut the three black together, the three white together, and the three ground together. If the junction box is metal you'll need to ground the box as well.
The best way to handle it would be to run to one of the outlets and pigtail in that box with the line to the other outlet, but a separate junction is acceptable as well.
Yes, this will be a 240v circuit. Should have said black, white and ground. No red on 12/2.
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