The Weekend Quiz. 6th April 2019. Electric Pressure.

Very close on the date Kelly. Very  close indeed.


Z.

Parts of the UK used 110v lighting (DC mainly)... the use of the terms 'undertaking' and 'mains' suggest the UK.  The wording might be from an early version of the electricity supply regulations?

Ah the BA unit..... IIRC the table lists the specific resistance of wires of different materials one metre long and 1mm  in diameter?  1864!

The terminology is similar to UK electricity supply regulations of the mid 20th Century but the reference to 115Volt supplies indicates an earlier date. It is probably parliamentary legislation from either the last two decades of the 19th Century or the first couple of decades of the 20th Century. As there was an "Electricity (Supply) Act" dated 1919, exactly 100 years ago, I suspect that this is probably the source.

Alasdair

My suggestion is appendix A of the second report of the committee appointed at the postal and telegraphic conference held at Hobart in 1892, where they are laying out some rules the safe operation for suppliers.


The committee is all Australians and New Zealanders except Mr Jas O Callender of Callenders Telegraph Co Ltd* (London and Sydney), though quite a few of the presented papers are from further a field, including a translated German one.


Interesting to see how much EMC was already an issue, with concerns expressed about leakage from electric trains and trams interfering with communications.


oh yes, here 
https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&d=AJHR1895-I.2.2.4.3&l=mi&e=-------100--1------2%22daldy+mcwilliams%22--

Appendix A starts about half way through and the key page has no '11' at the top, but beware as in the whole document, which is a composite document of many papers, it is not the only page with that no.


*(After a merger, Callenders Cables is the 'cc' in BICC, still associated with wiring accessories and making cable today)

Answer.


The info that I obtained was from a little pocket book entitled "Munro and Jamieson's Pocket Book of Electrical Rules and Tables. Eleventh Edition. Charles Griffin and Company Ltd. 12Exeter Street, Strand London 1895.


The book is advertised for use by Electricians and Engineers. By James Munro C.E. and Andrew Jamieson, M. Inst. C.E. F.R.S.E.


Matthiessens's Experiments were shown as tables of Specific Resistance in B.A. units of Metals and Alloys at 0 deg. C. A B.A. unit = 0.9889 legal Ohm. (B.A. Standards Committee of 1892, part of the Board of Trade).


Columns showed of wire 1 foot long weighing 1 grain, and


resistance of wire 1 metre long weighing 1 gramme, and


resistance of wire 1 foot long 1/1ooo inch diameter, and


resistance of wire 1 metre long 1mm in diameter, etc.


Ref. Q.1. The quotations come from Board of Trade Regulations &c, for Safety and Supply of Electrical Energy (Lighting Order 1889).


Z.

Ah well, by 1895 the culture of copy and paste from  few years before, rather than do any original thinking, was clearly already upon us.