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can you split phases

By davidpaulagnew ·
Can you take two phases through one hole and a nother phase and earth or neutral through a nother hole

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by TheChas In reply to can you split phases

This is a question for a licensed electrician.

Any answer you get here would be an opinion, not a hard and solid answer.

You need to follow code for your area.

I can offer an opinion if I know the what and where of the wiring.

Where does the wire come from?

Where is the wire going?

What are the holes in?

What type of wire?

Why do you need to split the wires up?
Is there a reason that you cannot enlarge the hole?

These are all questions that you would need to answer for an electrician to be able to provide an answer.

The counter staff at a decent electrical supply shop (not a home center) should be able to provide general guidance. You will usually find at least 1 electrician in a contractor supply center willing to offer a little advice "if" you treat him nice.

In the US, the National Electrical Code is pretty specific about what size wire and what amount of power you are allowed to wire in a box.
There are rules about free space in boxes, and maximum wire in conduit runs.

Generally speaking, if the box does not have a large enough hole for all conductors of a 3 phase line to fit through, you are either using over-sized wire, or the box does not meet code for the power requirement.

If you are running wire into an outlet box, I believe that all conductors for a given circuit need to enter through a single hole with the proper clamps or strain reliefs.
A standard retail outlet box is too small for a 20 amp 3 phase circuit.
A 20 amp 3 phase receptacle will not fit a standard single gang outlet box.
Keep in mind that "code" does require a minimum amount of wire extending from the box to allow for safe wiring of the socket.

The box needs to have room for both the socket and the wire.

We have a lot of multi-phase circuits at work, and I cannot think of 1 that has the feed lines split between entrance holes.

For portable cordage, you NEVER split the conductors out of the cord before it is in a box.


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by TheChas In reply to

Based on a little bit of research, I have to my satisfaction confirmed that all conductors of a single circuit must enter through a single opening.


Romex? (Nonmetallic sheathed cable)

* Not in buildings >3 floors (nonhabitable excluded) [336-5] [n/a]
* Min. 1/4in. sheathing into box (max. 1in.) [370-17c, local] [4405.4.1]
* Protect from physical damage [336-10b] [t 4301.4]
* Nail plate req'd when cable is < 1-1/4in. of stud edge [300-4a1] [t 4302.1]
* Clamped to box with approved NM clamp [370-17b, c] [4405.4.2]
* No clamp ok for one gang of plastic boxes if stapled within 8in. [370-17c.ex.] [4405.4.2]
* Bends must be gradual (5 times diameter) [336-16] [n/a]
* Staple within 12in. of box and every 4-1/2ft. & clamped to box [336-15] [t 4302.1]
* Attic access hole- protect within 6ft. of opening [333-12a] [4302.2.1]
* box too small for 3 x 12/2 Romex et-7 [370-16b] [4405.13]
* Basements, exposed under joists min. >#8/3 fig. e16 [336-12] [4302.4]

The critical item from the above is that a minimum of 1/4" of the sheathing on Romex cable MUST be inside the box.

If the box you have does not have openings large enough for the cable you are using, you need to find a larger box.


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by OTL In reply to can you split phases

First off - If you do not know, then invest in a qualified electrician to install it. Some questions that first need to be addressed;

1. What is the maximum current possible on the circuit?

2. How far is the outlet from the breaker ?

After these are answered then you can answer what guage is required (which affects how it must be installed) and after consulting the local fire codes and National Electric Code

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