A quiz, old time colour codes.

[Boater Sam]

Bought a box of old books at Adlington last Sunday, some interesting items, older than me!

Reading through I discovered a few things that I had heard about and some I had never considered.

So as a light relief a few questions for consideration. I bet there not many of us old times even that remember these.

Firstly three from a small book first published in May 1936, last impression of the seventh edition, 1948. I will withhold the title and author till later. No cheating and searching please, I doubt you will find these on the internet even.

1 The colour code for Wander Plugs? 9 different listed, purpose and colour used?

2 Colour code for fuses, from 60mA to 5A? 12 in all.

3 Colour code for the lead outs of mains transformers, Primary, HT secondary and 3 valve heater windings? 17 in all.

If this is popular I can find some more, even more obscure! I might even put up a prize for the best answers.

Sam.

[Dave Moll]

re no. 2, given that the range is from 60mA, I assume that the 5A is NOT the BS1362 coding.

[Boater Sam]

Correct Dave, this predates BS1362 by a long, long way. There is some similarity in the colour though but it is misleading.

[ms660]

60mA...Black
100 mA...Grey
150mA...Red
250mA...Brown
500mA...Yellow
750mA...Green
1A...Blue
1.5A...Light Blue
2A...Purple
2.5A...Yellow and Purple
3A...White
5A...Black and White.

Lawrence.

[Boater Sam]

Ah, got that the first time, well done Lawrence, from memory? Or do you have the book too?
1A is officially dark blue but we will not quibble as there is no mid blue. Also there is no 2.5A fuse in my list, its another point for you.

I wonder if you can still buy colour coded fuses in this range?

One down, 2 to go.

[ms660]

Originally Posted by Boater Sam

Ah, got that the first time, well done Lawrence, from memory? Or do you have the book too?
1A is officially dark blue but we will not quibble as there is no mid blue. I wonder if you can still buy colour coded fuses in this range?

One down, 2 to go.

My copy of Radio and Television Engineers' Reference Book. Hawker, Pannett etc.

It also gives the colour codes down to 10mA and up to 10A

Lawrence.

[Boater Sam]

Which year would that be Lawrence? I used to have a Newnes Pocket Book from the '60s but it went in the noughties sadly along with most of my other stuff.

[Dave Moll]

Originally Posted by ms660

It also gives the colour codes down to 10mA and up to 10A.

Go on then, why not complete the list?

[ms660]

Wander plugs:

Red...Highest Positive HT
Yellow...2nd " "
Green...3rd " "
Blue...4th " "
Pink...LT Positive
Black...LT Negative, HT Negative, Grid Bias Positive.
Brown...Highest Grid Bias Negative
Grey...2nd " "
White...3rd " "

Lawrence.

[ms660]

Originally Posted by Boater Sam

Which year would that be Lawrence? I used to have a Newnes Pocket Book from the '60s but it went in the noughties sadly along with most of my other stuff.

4th edition...1963.

Lawrence.

[ms660]

Originally Posted by Dave Moll

Go on then, why not complete the list?

Additions:

10mA...Green and Yellow
15mA...Red and Turquoise
25mA...Eau-de-Nil
50mA...Salmon Pink



10A...Orange

Lawrence.

[Boater Sam]

Lawrence has been swotting up on old time colour codes, hopefully. If it's all from memory it's better than mine.

Anyone else care to contribute before Lawrence wins all the pies?

[turretslug]

10mA fuse? Wow, what wire gauge was that in, how would you see if it was blown or not, and how long before it just oxidised through anyway?!

[kalee20]

Interesting convention for wander plugs! I seem to recall the Radio Designers Handbook listed a convention for wire colours - and brown was listed as LT or heater supply. Can't remember the others though I am sure red is HT+ and screen-grid is orange.

This would make the wire colour different from the plug colour, of course!

[ms660]

RDH4 lists transformer colour codes for US but not for UK, I think the old UK one was set by the R.E.C.M.F

Lawrence.

[Boater Sam]

Correct, red is HT.
But brown is a high potential loudspeaker lead.
Strangely I can find no orange used but you may be correct.
Sam

[vidjoman]

What about the US colour codes used in small pilot lamps (bulbs). Rather than stamp the bulbs with the voltage and current they used a number code but also coloured the small glass bead that inside the lamp that holds the filament support wires.

[Boater Sam]

What do you have for the US transformer colours Lawrence?

[Boater Sam]

Apologies Kalee, brown is a heater winding transformer colour too, you are correct.

Vidjoman, that's one I had forgotten, do you know the colours?
Sam.

[ms660]

Originally Posted by Boater Sam

What do you have for the US transformer colours Lawrence?

RDH4, Part 7, Chapter 38, Section 2:

http://www.paleoelectronics.com/RDH4/CHAPTR38.PDF

Lawrence.