Refurbishing table lamp... cord grip

Examining a table lamp I found the live conductor fractured & insulation erupting!

Replacing a lampholder, flex & threaded tube insulator is easy. Brass switched BC lamp holder w/red safety pin (will not turn on if a bulb is not present).

Adding a cord grip is not easy. This lamp (and many more) are custom glazed pottery, Troika style, just a hole in the side.

I notice the brass lamp holder has an "strain relief bar" where you loop back the insulated cores - like some ceiling rose fittings that do not use a slotted-disc around the cable sheath.

Does that meet the requirement of a cord grip, so I do not need one in the base?

Otherwise I will have to diamond drill the side and epoxy in one of those plastic nylon cord grips with a plastic side grub-screw.

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only other alternative is a side-outlet cord-grip lampholder boss, they are =A39. Ebay UK item number 270609429438.

Reply to
js.b1
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Not IMHO.

Traditionally a knot would be tied in the cable inside the pottery, to stop it being pulled out through the hole and putting strain on the terminations.

Somewhat better would be to form a loop in the cable and cable-tie it.

Better still would be to use a cord grip of the type you describe, on the cable, but not attached to the pottery. Even a p-clip with a nut and bolt would do.

Obviousjly better still would be to drill the pottery, but you have to weigh up the risks of the cable getting chafed in the hole vs the risk of destroying what presumably is one of the i/c Domestic's treasured home decor possessions.

Owain

Reply to
Owain

As Owain says, normal practice then was to knot the flex. This is only a partially effective cord grip, but in this case its fine as the lampholder has its own gripping arrangement.

Sounds like what you'd like isnt so much a cordgrip, but strain relief. I'm not sure how you'd add that to a Troika era hole in pottery, you could perhaps go from pvc to something tougher though. Or just accept that these things occasionally happen on old lamps

NT

Reply to
Tabby

Thought not :-)

P clip sounds good, however I found another type of strain relief: Essentially a piece of nylon flat bar with 2 or 3 holes in it through which the cable is looped. Does not require much of a hole in the base for access.

I do not like the aesthetics of the "side-exit" solutions, but I will do a test diamond drill of a similar broken pottery item and if not successful will have to go that route. It does at least give a proven off the shelf solution.

Reply to
js.b1

I think the side flex exit lampholders make it more likely that if the flex is pulled the lamp will overturn and get broken, with an exit near the base the lamp is more likely to slide along the surface and survive.

Owain

Reply to
Owain

It is an odd idea, I am sure they used to do it on some "standard lamps" which are the worst for stability.

Currently core diamond cutting the base, then I can pull out a loop of cable and fit a P-clip or nylon clamp. A bit of effort, but at least it is done properly.

Got to do a centre light next... that is really asking for a "del boy" moment because it is piggin 1960s hideous :-)

Reply to
js.b1

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "js.b1" saying something like:

What about a clamp-on grip with plenty of slack inside? Many lamps of that type used to use that, but whether it's still ok, I don't know.

Reply to
Grimly Curmudgeon

That is what I plan on, combined with the new lampholder which has "insulated-core strain relief", together with a flash new 15p plastic bush for the brass tube bit :-)

Before it had no bottom cord grip & no lampholder cord grip; with the live insulation erupting it reminds me to do the quarterly rcbo test :-) Chopped the hedge trimmer cable today, that is ok, it is the

13th tomorrow... wish the milkman would stop wearing the Scream mask... very offputting.
Reply to
js.b1

If you mean to fix the P clip in place, as far as I can see it would do nothing at all for strain relief. And it looks like thats the issue here, not cordgripping per se.

Personally I wouldnt drill troika for the sake of what is a very minor point.

NT

Reply to
Tabby

Undersized P-clip acting as a loose strain relief clamp. I will most likely use the simple 2-hole plate (sort of a modern take on the knotted cable).

It is troika style by a cornish artist (relative), he had tried to drill the base himself but just marked out where it was thinnest (it varies up to half inch, the items range from about 10lb to over 140lb built-up floor standing sculptures). They should have been cut before firing, but it got overlooked as kiln time is always tight. Meant a lot of diamond cutting after firing which is a terribly inefficient solution, a tile just has a hard skin, this is hard right the way through.

They are all heavy enough that the terminals took the hit. Should be a push-in 2 piece barb.

Contrast with a 1960s george henry lees lamp which has the smallest flex I have ever seen, white figure-8 "bell white", and physically unstable even before a shade is added. Pull on that flex and it goes airborne. That is condemned on grounds of being the most stupid lamp ever made. Then again, a lot of the glass vases (er, junk) being sold by M&S etc are poorly weighted and not remotely flat on the base. At least cut glass stuff stays put and has some weight to it.

Reply to
js.b1

I'm not convinced I understand what you're describing.

I'm not sure what you're referring to as "threaded tube insulator" -- is that the nipple on to which the BC lampholder screws?

You refer to a "just a hole in the side" -- is that an existing flex entry point in the base of the lamp but one that's simply too small to admit any obvious mechanical cord grip, or what?

If the only problem is that there's no mechanical gripping of the flex where it enters the base of the lamp, then use a bit of creativity. An excellent use for silicon mastic!

Reply to
John MacLeod

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