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I have an L14-30P connected as a suicide cord to a 5-15P through a 10/3 wire. The 15 side connects to a small portable generator and the 30 side a properly installed 30 receptacle on my home panel. There’s a manual interlock that prevents the receptacle and the home main to be on at the same time to comply with local codes.

I wired the suicide cord’s 30 side to ground, black on the right and white on top to neutral. I manually turn circuits on in the house that I want on - in this case I want my fridge and ceiling fans. The problem I have is that other appliances or plugs (most that are GFI) don’t work and I only have a fraction of things powered that I’m trying to turn on. This same issue doesn’t happen with my 30a to 30a generator cable I use with a larger generator.

Is the issue that the 30a was supposed to have 120V going to each hot side and I’m only powering half? The generator has an open/floating neutral if that helps.

Any input other than not using a suicide cable would be greatly appreciated.

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    With only one hot, your panel only has power on one side. Are the circuits/breakers not working, seem to be right below the ones that work?
    – crip659
    Jun 13, 2022 at 18:29
  • Actually no, I just went back and looked and there are circuits on the left and right that work and others that don’t but not side specific. I wonder if it’s wired cris-crossed under.
    – Adam
    Jun 13, 2022 at 18:48
  • 1
    @crip659 is trying to tell you they are cris-crossed. Most panels have alternating hots - i.e., top row left & right on Hot A, next row left & right Hot B, third row back to A. That way a 240V double-breaker "just works". Jun 13, 2022 at 19:02
  • 3
    Harper has a great colorful diagram showing this. But be warned - he will (appropriately) read you the riot act for doing what you are doing. The truth is, you could wire up a proper inlet and solve the problem without putting yourself (and everyone else around) in such danger. Jun 13, 2022 at 19:03
  • 3
    Adam break down and get a 30a inlet since you already have the interlock, then you put a female plug that mates to the inlet and it is safe and code compliant no chance of someone getting hurt or killed
    – Ed Beal
    Jun 13, 2022 at 19:31

1 Answer 1

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Use an ordinary cord as a cheap inlet

What the ---

--- sigh. I get it. NEMA 14-30 inlets are pricey. So....

  • Find an appliance cord of appropriate ampacity, with the plug that you want for an inlet. This can be salvaged off a broken appliance or just bought (e.g. NEMA 14-30 dryer cord).

  • Take it into an electrical supply and get a strain relief that allows that cord to enter a 1/2" or 3/4" standard knockout on a metal box. Figure $3-4.

  • Get a blank faceplate with that knockout, or better, a metal extension box for the box your "suicide" socket is now.

  • Install the cord into the strain relief, put that into the knockout, and wire the end of the cord into the circuit.

Look at that. A house connection that's a plug, not a socket, and didn't cost an arm and a leg. Now we don't need a suicide cord.

Mind you this is probbbbbbably a Code violation (I haven't really split hairs on 400.7/400.8), but it beats the living heck out of a suicide cord.

Wait. But now I need a 14-30 inline socket.

Well you already had a 14-30 socket, now you just need a new box to mount it in. That's fine, get an appropriate steel box such as a 4x4 deep box ($2-ish at electrical supply) and cover, and mount this right next to the above "inlet" and within reach of the cord! Got it? Out the bottom of this box, bring a common NEMA 5-15 plug/cord. So it's a double inlet that lets you swing either way.

Or you could just shortcut this and do the 5-15 cord straight.

DO NOT tolerate cords draped through cracked-open doors or windows!!!

I know you think the suicide cord is the dangerous part here, but you're missing the big one. Many people have generator inlets inside their house yet they run their generators outside. This inevitably leads to cracked-open doors to let the cord through, and this lets in carbon monoxide and kills them all. link 1 link 2 During hurricanes, generator stupidity is already the #1 killer of people, and often the only killer of people.

So I know you're expecting a smackdown for the suicide cord, I really need to give you a smackdown for the interior generator inlet. Move it outside. Cheap cord trick and all. I really don't care how, because anything you can do is less dangerous than an indoor generator inlet + suicide cord.

Your real question

OK, so USA power comes in 2 "poles" of 120V each, totaling 240V. Here is a wonderful video that also gives Europeans some snark (in other words: delightful). That video touches on how things are phased in the panel, but this answer goes into more detail.

These 2 poles means that your 120V generator is only feeding one pole. Can we fix this? Yes probably, but we MUST do an important step first.

Part 1: identify Multi-Wire Branch Circuits

This part is an absolute prerequisite, because we need to not set your house on fire. Your house may not even have any but this must be checked for.

Multi-Wire Branch Circuits (MWBCs) are 120V circuits where 2 hot wires share a neutral under controlled conditions, which do not set the neutral wire on fire. It is absolutely vital these be phased correctly. Current Code requires they be handle-tied, which on all but GE panels also assures they are correctly phased. (On GE panels best to use a 2-pole 240V breaker.)

I know you want to call them "2 circuits shared neutral" but they are actually 1 circuit with 2 hots.

So you need to search each circuit in the panel looking for any evidence of MWBCs. Typically a /3 Romex with red and black going to different breakers. Might also be a conduit with more hot wires than neutral.

Take special care that every MWBC is correctly phased (240V across the hot wires is correct), and every one is identified with a handle tie. This is essential for the next part.

Part 2a: there positively are not any MWBCs.

If you are positive your panel has no MWBCs, then you can do a simple thing: wire your one hot to feed both hots on the 14-30 socket. I know you're really tempted to do this without searching for MWBCs. Don't.

Part 2b: MWBCs identified.

Now you understand phasing and know where all the MWBCs are, you can move circuits around so the circuits you want are all on the same phase. For MWBCs, simply exchange the two hot wires. For others, move breakers around - you don't even have to disconnect their wires, you can rock them out and leave the wire attached.

If you need both legs of an MWBC powered, you have no viable option except a 240V generator.

Now with all your critical circuits on the same phase, wire your generator cord so that the generator feeds that phase.

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