Am stuffing three old 10ga. NM cables into a new, single-gang old work plastic box (i.e. just replacing the old box) and running into a ton of resistance (electrical pun intended). Which electrical cable lubricant might work best? I have tried nothing but the ol' heave ho and not gotten very far along. I tried straightening the wires out. I looked at metal old work boxes but they are really small.

Bought some electrical wax lubricant but can get any recommended brands for this purpose to make this task smoother.. already saw the gels...Will try electrical tape and a piece of scrap Romex to tape to old wires to get them thru the box flaps without just breaking off the box flaps... Does gel work better than wax?

  • Pulling old cables is a nightmare - copper work hardens and old cables have twist-kinks in them which cause them to bind in the conduit. Get a roll of new cable, set it so it can rotate as you pull then pull the cable straight off the drum steadily - this avoids loops and kinks.
    – Solar Mike
    Commented Jul 12, 2021 at 7:21
  • 1
    Don't really understand what's going on. Can you clarify?
    – JACK
    Commented Jul 12, 2021 at 12:55
  • How long is the run? Commented Jul 12, 2021 at 13:26
  • Not only how long is the run but how many bends” code allows up to 4 ea 90 degree bends but I can tell you that in some cases 3 will be the max depending on the radius of the bends, in the old days we used dawn dish soap as a pull lube today clear lube or poly water lube are brands commonly used by pro’s and in a pinch dish soap always helps.
    – Ed Beal
    Commented Jul 12, 2021 at 14:02
  • Sorry for the confusion. Pulling existing wires, ready in wall, stapled to stud from there into a new box only. Not through the walls or through conduit! About 8" run max. Stuffing 3 Romex cables into those dang plastic box flaps on a single old work box. I'm not muscle bound! Will try pulling with an existing piece of Romex taped to old wires. Also want opinions on wax versus gel lubes from electricians or those who have used them.
    – DAS
    Commented Jul 12, 2021 at 21:12

5 Answers 5


You need something like this. Alternatively, when a friend of mine was working a weekend project and couldn't get it bc supply houses were closed, he went to a pharmacy and bought like a dozen bottles of KY jelly. I couldn't imagine what the person running the checkout register thought.

wire lube


You are pulling existing cable (Romex, NMD90) through box openings for a new box, and you are experiencing mechanical difficulties. There is no conduit.

I believe your mechanical challenge arises from the orientation of the tabs/box holes and the stiffness of the cable.

If you have access to the cabling behind the box, unclamp them and run them through the box holes and reclamp them after the pull. This provides more freedom for the cable to flex to the opening without requiring a tight turning radius.

Alternatively pull the cable before mounting the box; slide the box over the cabling, so to say.

It helps to make sure you pull in the opposite direction of where the wire comes from. So if the cables enters at the bottom of the box, pull up into the box, inch by inch, not forward out of the box. Pulling outward requires a tight turning radius that the cable can not produce, and increases friction against the tabs.

For better grip inside the box, use a pair of pliers and pad the nose with electrical tape, or use gloves.

If you add a picture of your situation maybe we can help more.

  • If I could give hearts, i would! You explained it perfectly. I am pulling the cable before mounting the box.Romex is stapled on all 3 runs to a stud. Can't unstaple, pull the wire and then restaple as the box will ease itself into the hole...unless I cut out adjoining drywall to accommodate my hand... Can barely get hand in there as it is to push wire past flap. Taped pliers. Didn't know about pull direction but that helps a lot. Tried taping spare piece of Romex onto cables in box and nearly fell backwards pulling! Maybe I need to open up drywall and use a nail in box.....
    – DAS
    Commented Jul 13, 2021 at 0:01
  • @DAS I'm glad that was so helpful! Now that you have a new approach, good luck with it.
    – P2000
    Commented Jul 13, 2021 at 0:18

Before you even think about using lubricant, have you straightened and smoothed the wires before attempting to insert them? Taped the tips together if necessary? Considered a metal old work box with screw clamps for easy insertion? Deburred any adverse molding marks or seams on the clips? There are 5 or 10 types of single gang old work box that might be legal in your area and some might be vastly easier to install than others.

Examine the part that must pass the squeeze clip for any ridges that can be temporarily taped and examined the box for any hard edges that can be bevelled without hurting the integrity of the box. Can you pre-place a tool like a wire hook to help guide the wires if they're out of finger reach? Depending on the order of how you're trying to insert the cables in the box and insert the box in the wall, you may need to pre bend the cable into a shape that will allow it to move with only linear friction when you pull it into the box.

Lube has a very limited chance of helping you because usually in this situation it is the bend and shape of the wire or an edge or hook creating the problem, rather than simple friction, which lube will help with. Thoroughly examine what you're trying to do mechanically, because excessive forces that would require lube can damage the wire, and the you need to replace the entire length of the wire. Avoid any situation that will tightly or repeatedly bend the wire. Different types of wire casing have different amounts of surface friction and abrasion resistance, so be aware of that. Sharp edges can be bevelled and/or taped over, and the same can work for cloth coatings, that fray, poof and bunch up.

You need to add to your question where you live, whether ground wires are present and the volume of the box you intend to use. Method of calculating necessary box size varies by region. Is it the largest box available? In some cases a box of a different type or size might be much easier to install without cutting more drywall, although that could necessitate a special cover. Fully consider your situation, including cutting and patching wallboard before you risk wrecking your wire and necessitating a lot of additional damage and expense.

Worst case scenario if you damage them is probably ripping drywall all the way back to the panel and to the other branches in order to install new wire. This may necessitate additional inspections and renovations depending on your local code.

If you don't feel confident before you begin, bear in mind the hefty cost of a professional visit is likely much smaller than the cost of a bad error.


The industry uses ASTM D 3487 oil to insulate and lubricate electrical apparatus. This is essentially mineral oil or baby oil.


I was working with old, bent 10g wire. I ended up carefully straightening, then straightening again each wire and making sure it came into the box directly over/under the flap and not the sides of the flap. Did not need gel or wax.

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