Interesting things turning up as I tidy the electronics lab...

[Lucien Nunes]

After being on the road day and night for ages, I've got a month of solid R&D / workshop-based projects to do so I am having a general sortout here at the workshop and especially the electronics lab that has been piled high with odds and ends.

Oddball No.1. Have a look at this tumbler switch. Just an old lightswitch, right?

 

[Kamikaze]

To me that looks like the Carter switching system. The neutral would be on the L/H Switch opposite the incoming feed (The terminals that are normally used for the strappers). But you have stated that they are one way switches and that is baffling me.

 

[tazz]

This is really interesting, can only think the cable is micc, and the uninsulated cable is the copper sheath. Are they waterproof switches or switch rheostats, like the old external ones used in public buildings...?

 

[Barry White]

To me that looks like the Carter switching system. The neutral would be on the L/H Switch opposite the incoming feed (The terminals that are normally used for the strappers). But you have stated that they are one way switches and that is baffling me.

not heard of that method just had a look on google interesting unconventional method frowned on today thanks every day is a learning day

 

[davesparks]

Is it just plain old concentric wiring?

 

[Dave OCD]

It's a PME/TNCS socket from long ago with combined neutral/earth at the socket ??!!

 

[Lucien Nunes]

Not TN-C-S but real traditional TN-C with the PEN all the way to the load. Or as it was called, Earthed Concentric. The cable is Stannos. More later....

 

[SPARTYKUS]

To me that looks like the Carter switching system. The neutral would be on the L/H Switch opposite the incoming feed (The terminals that are normally used for the strappers). But you have stated that they are one way switches and that is baffling me.

I like your picture of a man in a bin. Is that a hot tub.

 

[DuaneMHunt1976]

Can you still use toggle switches for lighting then

Guessing by rights the Switch itself should be earthed

Just woundering as i do have a 4P2T 6A switch some were

 

[davesparks]

Yes of course you can use toggle switches, lots of manufacturers make them in their fancy decorative ranges

 

[Kamikaze]

I like your picture of a man in a bin. Is that a hot tub.

HELP!...I’m stuck that deep inside of it, whoever pulls me out will be crowned king Arthur.:jester:

Not TN-C-S but real traditional TN-C with the PEN all the way to the load. Or as it was called, Earthed Concentric. The cable is Stannos. More later....

We like guessing games. Keep ‘em comin bro!

 

[Lucien Nunes]

Stannos was specifically designed for use as earthed concentric, suitable for damp locations, before MICC took up these roles. It was a single copper core insulated with rubber and paper tape, inside a tinned copper sheath with a hermetically sealed seam. The 'Kuhlo' cable that Mykey mentions was similar but usually multicore.

From the early days of earthed concentric, concern about the sheath or containment becoming live on the load side of a bad connection led to extra regs regarding installation methods. You could rely on a conduit thread to make a connection (e.g. a screwed spout) but not a bush and locknut through a CI box that would otherwise be acceptable as a CPC. At these switches there's an almost indestructible connection from each sheath to the next as they are sweated into the brass plug. The spare entries at the socket have the neutral pigtails soldered in.

Advantages of earthed concentric for this work include small size (this cable is 1/.044 i.e. 1mm² but only 4.5mm diameter overall) combined with low voltage drop (the sheath is more than 1mm²). Every cable and every point automatically has a neutral available, which takes a bit of getting used to. Cores are only ever used for the line, so it makes perfect sense to loop at the switch rather than the light.

Is this possibly the smallest cable ever made for LV installation work? The only thing I can think of that betters it size / performance wise was 2-core 0.0015 sq in. 250-volt grade Pyro, which IIRC was 0.187 ins diameter (4.75mm), smaller than 2L1 and one of my favourite cables because it could go where nothing else could. Makes 1.0 T+E look a bit clunky!

 

[GB.Kayak]

It's an early example of an intermediate switch, that can be used as a general purpose double-pole changeover, made by Lundberg. They made a range of special-function 'Marvel' switches and promoted improved switching schemes e.g. for multi-circuit light fittings controlled from multiple points with a single control, even providing booklets to show how to connect them up. This one has a sticker on the back showing its use to reverse the polarity of a DC circuit, e.g to reverse a motor or stop fluorescents blackening at one end due to mercury migration on DC mains. But by linking the each pole's N/O to the opposite pole's N/C you can use it as an intermediate.

Of the three moving contact blades on each side of the mechanism, two are connected together and the third connects to another blade hidden deep in the ceramic base, that swings up into the fixed contacts instead of down as usual. You can just about see one of them to the left of the + terminal.

View attachment 29555View attachment 29556View attachment 29557

I like the angled terminal screws ... detail seems well thought out to me.

 

[Lucien Nunes]

This was in one of the drawers of special wiring tools but should really have been sent over to the museum workshop. It's for wiring - what does it do? I need the name...

 

[electron1]

Complete guess, something to do with making Ross Courtney terminations?

 

[Lucien Nunes]

Wow, got it in one! Well, near as dammit, it's a Collett one but basically the same animal. For anyone who hasn't encountered them, before crimp technology was perfected there were really three ways of making off a wire to a stud, which was a much more common method of termination than it is now:
1) For solid wire only, form a loop (with your loop-forming pliers!) and clamp it between two washers.
2) Solder into a lug or onto a tag
3) Ross Courtney / Collett terminals.

You lay the wire around the spiky bit, drop the washer on top and clamp it together with the tool. The fingers fold around to retain the washer and make a neat ring on the end of the cable. Technically it's not a crimp as it uses the pressure of the nut on the stud to hold the wire in contact with the terminal, but they were effective and very widely used on panels and plant. I could really do with finding a big stock of old terminals for use in restoring vintage equipment.

The last pic shows inside the back of a substation control panel that is wired throughout with Collett terminals.