Glass Message Board

Glass Identification - Post here for all ID requests => Glass => Topic started by: Bernard C on August 25, 2012, 05:15:28 AM

Title: Glass Scruits? - verdict no or extremely unlikely
Post by: Bernard C on August 25, 2012, 05:15:28 AM
Scruits are old small tumbler-shaped porcelain wire connectors with a sharp internal screw.   They have never been given a British Standard, so have not been used as permanent connectors here for 50 years or more.   I use them (with the power off) as temporary insulators when wallpapering or decorating — much easier than trying to do it with a socket or switch just lifted off the wall a little, and it gives you a chance to thoroughly clean the socket or switch.

Looking them up on the Internet out of curiosity, I discovered that they had been made in plastic as well.   This surprised me as I thought the sharp internal thread was an essential feature of a scruit.

Does anyone know if they have been made in glass?

Bernard C.  8)
Title: Re: Glass Scruits?
Post by: Ivo on August 25, 2012, 08:33:39 AM
Hopelessly outdated - we now use special clamps to secure the ends of wire as an end or as a single through connector. The screw type was deemed unsafe and could lead to shortcircuits and fire. Never seen them in glass - perhaps because that is too smooth.
Title: Re: Glass Scruits?
Post by: Gary on August 25, 2012, 09:00:55 AM
I think you have used the wrong terminology(ie short circuit), the main reason for them being discontinued was you could not be sure the connection between the two or more wires was tight, if the connection was not tight it would cause over heating at the connection (scruit) and possibly result in a fire. Quote from Wikipedia "A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path, often where essentially no (or a very low) electrical impedance is encountered. The electrical opposite of a short circuit is an "open circuit", which is an infinite resistance between two nodes. It is common to misuse "short circuit" to describe any electrical malfunction, regardless of the actual problem".
I have never seen glass scruits in my time as an electrician in Britain.
Gary
Title: Re: Glass Scruits?
Post by: Bernard C on August 26, 2012, 04:15:11 AM
Ivo and Gary — thanks.

Nearly forty years ago I bought a huge Victorian semi in Stafford, probably the largest semi-detached house in the town.   The wiring was vintage, an old DC system which had just about been converted to AC, so I went on a house wiring course at the local college, and got a lot of advice.   I actually took the course twice, once using conventional cable, and then a second time using Pyro (mineral insulated) cable for external use.   The tutor was a fan of scruits, not as permanent cable connectors which he stressed was dangerous, but as:
  • temporary insulators while you are decorating (with the power off),
  • temporary cable connectors when you are testing continuity, and
  • the simplest method he knew of twisting two or three wires together before screwing them into the back of a socket or switch.
    • Bernard C.  8)