ECN Forum Forums Photo Discussion Forums Electrical Nostalgia Vibration Wire Nut

That a Marr connector.

Now they come with a Roberson screw head

Doug,

Were they used where vibration was an issue? Like I said, I just heard them called "Vibration" wire nuts but no one could give me the right name. Till now.

twh,

is Marr a trade name or just a style of connector?

I think it's the name of the inventor. The company that made the original Marr now makes the Marrette wire nut. By now, the name might be like kleenex is to facial tissue, but I'm not sure if anyone else makes that type of connector. When I went to school, they had specific instruction on not twisting the conductors unless one was stranded and the other solid.

And remember to put the thread on first towards the insulation, otherwise the cap doesn't screw on far enough to cover the bare wires.

I think it's another Canadian thing.
They are still available and sold as anti vibration.

http://www.tnb-canada.com/en/catalogues/online/comresconstruction/pdf/c5/01_marrcat_e.pdf

I was going to say that only my northern neighbors seem to know about this type of wire nut. I never saw lots of these connectors but I was out in the field from 1976 to 1998 and I think I only saw maybe 2 dozen or so.

Harold, I've never installed one and I've been around as long as you have. A couple dozen is about the same number that I've run into, too. To add to jdevlin's point, some of them were backwards.

I think a vibration wire nut is a normal wire nut tightened with pliers.

Looks like someone crossed a wire nut and a European "choc block" style connector