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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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15th Jun 2022, 4:19 pm | #61 |
Heptode
Join Date: Oct 2019
Location: Täby, Sweden
Posts: 692
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Re: Tin Foil - makes you weep
That's what makes a Swiss 3 pin plug such an elegant solution ...
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15th Jun 2022, 4:24 pm | #62 | |
Heptode
Join Date: Oct 2019
Location: Täby, Sweden
Posts: 692
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Re: Tin Foil - makes you weep
Quote:
Each block of circuits has its own RCD, so that nuisance trips do not interfere with critical circuits (e.g. bulb blowing). All circuits are max 10A unless it is a feed to a cooker or other high powered device, which is 3 phase @ 16A per phase in my house, but could comfortably be 10A. |
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28th Jun 2022, 2:46 am | #63 | |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: Tin Foil - makes you weep
Quote:
Consider for example a system with 3 phase, 4 wire mains at 127/220 volts. A consumer requiring 220 volt supply would be connected between any two phases and would need double pole fuses as either pole was live at 127 volts to earth. Later the supply might be modernised and changed to 3 phase, 4 wire at 220/380 volts. The supply company would change the connections at the service cut out in order that the consumer still received 220 volts. The existing two pole fuse boxes would likely remain. Other systems might have been single phase, 3 wire at say 120/240 volts. Consumers requiring 240 volts would then be connected between both poles of the system and need double pole fuses. Later the supply company might double the voltage to 240/480 volts and change the connections in the cut out in order that the load is now between the previously unused center wire and one pole of the supply. The old double pole fuse boards would remain. Single phase 3 wire was popular in areas previously served with 3 wire DC as the same mains could be used. There is STILL some in use ! |
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28th Jun 2022, 12:09 pm | #64 | |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: Tin Foil - makes you weep
Quote:
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28th Jun 2022, 12:11 pm | #65 | |
Octode
Join Date: Jul 2004
Location: Dundee, UK.
Posts: 1,797
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Re: Tin Foil - makes you weep
[QUOTE=broadgage;1480926]
Quote:
PMM |
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28th Jun 2022, 1:56 pm | #66 | |||
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: Tin Foil - makes you weep
Quote:
If however the existing cable had a reduced neutral, as most DC mains did, then that could be a problem. Many existing 3 wire DC mains with a reduced neutral were reused for AC supply but this was best done with single phase 3 wire AC on which a half size or smaller neutral is fine. Some remain in use today. |
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28th Jun 2022, 3:43 pm | #67 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
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Re: Tin Foil - makes you weep
I wonder if double-pole fusing was used to facilitate testing of individual circuits? I have a late Victorian GEC catalogue that includes house wiring diagrams, where the light switch was in the L conductor and the fuse in the N conductor. Removing the fuse and turning the switch to the OFF position allowed the circuit to be tested without disturbing any wiring. Regular testing seemed to be more of a thing when electrical installations were in their infancy, and as the installations of the day were 110V or lower, a blown fuse that left a lampholder live would not have been considered hazardous.
Last edited by emeritus; 28th Jun 2022 at 3:48 pm. |
28th Jun 2022, 5:21 pm | #68 | |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
Posts: 2,529
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Re: Tin Foil - makes you weep
Quote:
AFAIK the supply in the town was initially DC so it all kind of makes sense. |
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28th Jun 2022, 7:53 pm | #69 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,172
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Re: Tin Foil - makes you weep
In Sunderland in the 30's the corporation electricity enterprise cabled up the streets with a 3 phase+N supply fed from distribution pillars. This was at 240v/ 440v and may in those days have been 40Hz
They ran a scheme called "hired wiring" whereby you paid for the work on your quarterly electricity bill as part of the standing charge. This covered the installation of service cut out, meter and 2, double pole switchfuses neatly mounted on a varnished ply board fixed to the wall with pot insulators. One switchfuse (5A) was for lights (main rooms only) and the other for a single 5A, 3 pins socket outlet, run on 7/029 and fused at 15A (so room for expansion). These were new installations but still used DP fusing Ed |
28th Jun 2022, 9:32 pm | #70 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
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Re: Tin Foil - makes you weep
Those paired switches with wood links were a standard GEC product: - extract from the 1912 GEC catalogue attached.
Also the house wiring plan from the 1893 GEC catalogue. It does actually say that the switch may be in either conductor. The catalogue also has a plan for warehouse lighting that has double-pole fusing but I haven't scanned that. |
29th Jun 2022, 8:15 am | #71 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
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Re: Tin Foil - makes you weep
The 1893 wiring of a "private house or mansion" was interesting on a number of levels. Apart from the fact that it is astonishingly early for electricity installation (late Victorian) it shows the WC right next to everything to do with food preparation and storage
Craig
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29th Jun 2022, 8:49 am | #72 | |
Nonode
Join Date: Jan 2016
Location: Stafford, Staffs. UK.
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Re: Tin Foil - makes you weep
Quote:
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29th Jun 2022, 12:13 pm | #73 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
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Re: Tin Foil - makes you weep
990The catalogue introduction refers to GEC's 10 years' experience working with contractors and manufacturers. It includes lots of equipment for small-scale private electricity generation as well as large plant for central generation. Lots of choices for local power for driving your dynamo: water turbines, oil engines, gas engines and steam engines. Only DC dynamos with battery storage, apart from an AC generator for experimental and laboratory use. 1893 was the year Swan's light bulb patent expired. The catalogue shows both Swan's lamps and GEC's own brand lamps (Stella) that they were then only selling abroad, and which would become available in the UK after Swan's patent expired, and looks forward to the construction of what would become the "Robertson" lamp factory at Hammersmith . A range of domestic and light industrial electrical appliances was available: - kettles, frying pans, toasters, irons, glue pots etc.
Last edited by emeritus; 29th Jun 2022 at 12:21 pm. Reason: Mention of the Robertson factory added |
30th Jun 2022, 3:43 pm | #74 |
Triode
Join Date: May 2022
Location: Kirckcudbright, Dumfries and Galloway UK.
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Re: Tin Foil - makes you weep
One of my colleagues from a while ago served his electrician's apprenticeship down a pit. He claimed that on one memorable shift they had a task to disconnect something from a junction box. The foreman asked 'What do we do first, Michael?' To which Michael brightly replied 'We isolate the junction box!'. Having done that, to his own satisfaction, and opened the junction box, the next question was 'What do we do now?'.
'Well, we unscrew the terminals on here'. 'No!' was the reply, and the foreman threw a three-pound hammer into the box. There was a huge explosion, and all the lights in the pit went off. Much later, once the lighting had been sorted out, they could see the hammer head welded across the terminals, and no sign of the wooden handle at all. This was, of course, because they had gone into the wrong junction box. There's a lesson in there somewhere. |
30th Jun 2022, 3:49 pm | #75 |
Heptode
Join Date: Oct 2019
Location: Täby, Sweden
Posts: 692
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Re: Tin Foil - makes you weep
Never assume. It makes an ass out of u and me.
Trouble is you need a few near misses like that one to develop the self-preservation skills, or you have to be trained properly so that they become part of your backbone. That is what seperates amateurs from professionals, IMO. |