These are photos from a domestic installation in the UK. Probably dates from the 1960/1970s. All of the items are in working order and still in daily use.
40a_service - Incoming underground service, located on the ground floor. Fairly typical of older UK installations:
40a_ferranti_meter - closeup of the all-mechanical electricity meter. Rated 40A , 240 volts. From here, a mineral insulated cable (mims/micc) goes to the 2nd floor to a metal Wylex panel.
wylex_metalclad - outer view. The original rewireable fuses have been replaced with plug-in circuit breakers, probably around 20 years ago. The whole unit is recessed into the wall, the routing of the cables is unknown:
wylex_open - interior view. Most of the property is wired in MICC. The black box above is a doorbell transformer. Earthing is provided via the metal sheathing of the cables, so no earth wires here. The large green/yellow wires are equipotential bonding to the gas/water services, this looks to have been added very recently (plastic mini-trunking at bottom right).
The breakers are rated 30A (red), 15A (blue) and 5A (white). These allegedly supply cooker, socket outlets, water heater, lighting and another set of lighting - but someone has made various modifications since the original install, and some of the lights are now powered from the 2nd 30A breaker. You can see from these ratings that the 40A meter downstairs is grossly undersized, even allowing for diversity:
freidland_tx - the doorbell transformer. Not connected, the circuit breaker has been removed, so probably defective:
mem_singleswitch, mem_dualswitch Light switches, single and dual gang:
[This message has been edited by Webmaster (edited 02-11-2007).]
mem_singleoutlet - socket outlet. The white cable from the lower right is a more recent hack-job, this goes to another surface mounted socket outlet nearby. Most of the others in the property have been extended in this way:
cooker_control_mk - older type control for an electric cooker. Metal face with a plastic insert. This works, but the whole assembly is now loose from the wall and the insert is loose also:
rose_closed, rose_open - older type lighting rose, ceiling mounted. This one is on a sloping ceiling hence the odd angle of the flex. The drop-wires are modern, everything else is not:
rose_wires - closeup of the interior of the lighting rose. Although terminals are provided for switch and loop wires, these are not used; there must be other junction boxes elsewhere in the ceiling void:
sadia_heater - electric wall mounted water boiler. Kitchen sink immediately below. There is a larger model of this heater elsewhere in the property which supplies hot water to the bathroom:
Nice job! No gland on pyro sub-main. Copper pyro clip used to form an earth connection to sheath. BS951 clamp onto lead PILCSTASC. No grommets where cable exits to friedland transformer. Arguable as to whether the use of red / black sleeving on the pyro coming out of the meter constitutes 'double covered'. I would hazard a guess that the lugs within the switch boxes are also plastic, and I would like to see inside the switch and socket outlets to see how the cables are connected. My guess is that it is with pyro pot clamp boxes...the work of the devil...and that the walls are sand and cement rendered [this causes corrosion of the earthing connection as this is just an interference fit between a galvanized steel box and a brass pot]. It also looks like it could be a 'Council Job'...never seen a domestic installation done totally in Pyro in 35+ years. Also as a 'side observation' I am guessing that the job is somewhere south of Birmingham area; reason?...for some weird reason all the twin and earth cable south of Birmingham used to have a white sheath whereas in the North it was grey.The cable going to the transformer appears to be white sheathed. Now apparently white is for LSOH and grey is for pvc.
[This message has been edited by TrimixLeccy (edited 02-12-2007).]
The lightswitches have metal back boxes. The wires enter the backboxes from within the wall, the end of the cable is inside the wall. The connection between the cable and backbox is not visible, but there is a connection as the backboxes are connected to earth somewhere. There are no grommets, the wires just come through a knock-out hole in the metal.
The sockets have a similar arrangement, with the earth being a short length of wire attached to the backbox with what looks like a woodscrew. Under the floor the joists are notched and the cables just laid in, so the cables are in contact with the back of the floorboards.
As for the lighting, the pots at the ends of the cables are clamped onto the back of a metal box which is behind the black plastic rose as shown in the photos, there are evidently connections inside there. I have not removed any of these as the wiring is fragile enough already, but looks like the standard UK loop system (in/out/switch).
The location is in Bournemouth, so about as far south as you can get. The grey/white cable is certainly true, until a few years ago grey cable was a rarity here. The property is currently rented out and allegedly had an electrical inspection done 18 months ago. Of course, no documents exist regarding that or any other inspection. No labels on the CU either, personally I don't think anyone has inspected this since it was installed.
The lighting on the 30A breaker is a recent change - someone has connected wall lights using 1.5mm twin&earth directly into the back of a socket outlet, from there to a junction box with further T&E cable to the lights and the light switch. No fuses anywhere, and the light switch is a 2 gang one, one gang on the the original 5A lighting ciruit and the other from the 30A ring final.
see page 3 of the catalogue http://www.electrium.co.uk/Appleby2003(4).pdf
These are renowned for loss of earth continuity when installed in sand and cement render. years ago you could buy socket and switch boxes with the clamp attached, seem to be favouring the retrofit clamps now. MK used to make a surface version in plastic with integral clamps. Great idea if you use earth tail pots, not too good otherwise. Mind you, I liked heat shrink pots and the BICC Pyrotennax two part plastic pots [I will post some pics if I can find them] Whilst on the subject of MICC; anybody remember ALCuMICC?...now that WAS cr4p!
I've heard about this north/south gray/white cable divide before, but I wonder just when it supposedly started.
Does anyone know when white-sheathed cable was actually first on the market? I'm guessing not until the 1980s, or possibly late 1970s.
Pre-metric PVC cables were always gray sheaths as far as I know. I've certainly never seen any Imperial-sized cable in white, and metric cables I've seen (from living in Luton, Cornwall, Lincolnshire, and now Norfolk) which clearly date from the earlier 1970s all seem to be gray as well.
On a different tack, I like the old metal-clad Wylex Standard panels. Well made, a reasonably good internal layout, and far superior to a lot of the modern stuff in my opinion.
Here are 2 links to the ECN server [hopefully] if not I will ave to get Pauluk to put them straight onto the page. First pic is a dismantled Pyro gland [about the same age as the ones in the above pics. Newer ones are slightly different] so that the uninitiated can see the composition. The second pic is a selection of the tools neede to terminated the cable. One or 2 items are missing, I will post them when I find them in the workshop
(edited to post images)
[This message has been edited by electure (edited 02-14-2007).]
Top photo On the left is a pack of 1960's 'pots'. These comprise [surprisingly] of a brass pot specific to the size of the cable diameter. On the box are shown 2 little 'spots'. These attach to the plastic sleeving below the level of the 'biscuit' [disc with holes in it] The cable is stripped and the pot screwed on until the sheath just enters the pot base. The cores are pulled straight and the biscuit, spots and sleeve attached . The whole lot is then slid down until the pot rim is reached. This serves to fan out the cores. The biscuit assembly is then withdrawn slightly and the pot filled with 'compound'.The biscuit is then fitted and compressed/crimped to the pot. After termination of the other end the whole assembly is tested for earth leakage at 500v for our 240 / 415v systems. Note; it has actually taken longer to type this than it does to terminate a 2 core cable!! The 2 yellow boxes contain a later version of the same items. Sizes used to be measured in 1000th of an inch and number of cores; soa 263/3 was 263/1000" outer sheath diameter of a 3 core cable. The remainder shows a old style blown-up temination [unfortunately the bits are in the wrong order. The 3 part gland fits before the pot and seals to it by compressing the 'olive' between the 2 parts of the gland body. note that the sleeve is now fitted with the 'spots' attached to the sleeving. This sleeving is passed through the biscuit from the rear after being cut in half. Cleanliness is paramount in this type of termination, but done correctly the assembly is 'fire rated'. Get it wrong though and....
from the top. Sheath stripper: fit gland through large hole as a 'former' put cable through the gland and rotate the handle. This forma a spiral cut down the sheath like sharpening a pencil. Next pic, a BIG Pyro bender that I made out of some bar, 2" diameter pipe and a cut up welding gauntlet. [bottom pic is of an adapted factory made bender] The middle pics are of different types of pot seal crimper,all still usable today. My favourite is the 'vise grip' in the centre. A rare and sought after item today. The 'black sleeve' is for fitting AlCuMIC and MICC wedge seal pots [now discontinued but I will post some pics when I find samples] When sleeve is retracted this tool can be used on todays pyro. Other tools not shown, because I cannot find them!! would be, a ringing tool for forming a straight cut edge to the sheath prior to screwing on the pot along with a pot wrench. A good Electrician can usually complete the termination with just a set of decent side cutters, pliers and a crimper; but it takes years of practice. This type of termination [gland and screwed pot] is suitable for use in explosive atmospheres and within petrol pump housings subject to type approval of the assembly and suitable stamping accrding to BS 7671