I'm converting a 240 to 120 split circuit receptacle.
Here's what I know:
- 240v receptacle (red, black, bare)
- White wire is available
- Double pole 20 amp breaker
I don't know if the white wire is attached to the neutral bar so I'll have to check it.
Planned:
- Split 120v receptacle by breaking the bass tab
- Black wire to top brass lug
- Red wire to bottom brass lug
- White wire to silver lug
- Bare wire to green lug
Items that will be used are a welder and a LED work light.
Spot any mistakes in my scheme (bad pun intended)?
The plan is solid but I don't think that's legal, sharing a neutral like that, or putting both phases on one receptacle. Though I think the neutral will work ok (not overload) because the hots out of phase, but don't quote me on that.
Thanks Kenny.
I checked the NEC 2011 (per info pulled from state codes) and it appears "ok" based on my understanding if
- Use a double pole breaker that shuts off both circuits (this currently in place)
- Group the wires of the multiwire branch with tie wraps unless the circuit enters from a cable or raceway (have to verify)
I didn't find anything indicating spliting the receptacle as bad as long as I follow MWBC (Sec 210.4).
That's pretty much how a couple outlets in my house were ran back in the 80's when it was built. 3 wire with a ground, they shared the neutral and had the brass on the hot side cut to separate the circuits. They then went back to another junction behind a light that shared a 14/2 wire to 4 other outlets.
Electrician = 0 and SZ = 1
- Removed the panel from the breaker box and found the 240v outlets (I have two) in separate raceways. Check!!
- Red and black wires showed 240v. Check!!
- Flipped the breaker off and relabelled the panel
- Removed the 240v outlet and installed the 120v outlet (w/ tab removed on the brass side) per MWBC diagrams. Flipped the breaker back on. Black and white = 120v; red and white = 120v. Check!!
- Flipped the breaker off and receptacle is dead. Check!!
Saved $95 . . .
Looked that up, seems that is legal, cool stuff.
I'm a little late to the party, but this all seems well within reason, code-wise and standard practice wise.
The big thing with this kind of install is the double pole breaker with single handle (I'm assuming Square D?), or a breaker with handles that are interconnected. If the smoke comes out of either part of the receptacle you want both "circuits" to turn off at the breaker. Otherwise you have bad biscuits for the baker.
Sharing a neutral isn't the end of the world- immediately. I don't believe there is anything in the NEC that prevents it. But best practice is to isolate the neutrals by circuit. Ultimately what happens is a circuit is installed to hand a given load. As time goes by and the loads change you run the risk of overloading the neutral wire. It happens.
Yup double pole breaker with one handle from Square D. One circuit will be for the welder and other is a light. As visual reminder the outlet is a different color.
In reply to Strike_Zero:
The only other thing I would do is label the breaker and the receptacle. That way when you sell the house or have an electrician do work, they won't get surprised.
Good call . . . I only labelled the panel.
Label the outlet cover plate front and back.
