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trying to fix a dysfunctional booster-starter-charger. there is a large chinese relay (part nr WJQX-38F-2H) which has a funny little set of diodes which seem to ahve been connected across the coil terminals. I would have expected a diode in this position on a DC coil but Im not sure what the...

thanks all. indeed this stuff is regularly used on decks of workboats so loads of oxygen, salt & sunlight. the braid seems to have a very short life as the rot gets in rapidly and you can see its rusty through the transparent jacket. I think it is transparent so that punters in a shop are...

very interesting. case in point at the moment are the deck power cables for containerised diving air-compressors and containerised hyperbaric chamber. (in use with 5-pin 32A 400V 3-phase plus neutral site-type connectors) would this be an appropriate cable for use in this context?

does SY cable have a practical place within any interpretation of a British Standard? what is it actually for? why does it *always* have a transparent outer jacket? in my own provincial orbit, the popular view is that it is Armoured Cable. I believe that it is strictly not armoured. I...

A friend has a Worcester green star heat slave ll, he diagnosed problem - weather had got into control PCB and caused a mains short on the PCB which destroyed part of the track. he took the PCB to me and I cleaned it up, repaired the tracks, meggered the mains input line which was OK at 250V...

this thought crossed my mind too but that will lose precious watts won't it? plus wanted to keep it as s i m p l e as poss.

I have an idea but I'm sure I am missing something possibly to do with efficient power transfer, hopefully some of the erudite contributors to this forum can comment: Consider a cheap "chinese" wind turbine. nominally 24V 400W, price about £140 ex ebay. They are what they are. Ive got experience...

well quite, I was going to say that it begs the question, how did you size the working conductors....

Thanks. more questions though! what are I, t and k? (I'm guessing basically I is some nominal current value, and k is some resistive coefficient of the conductor... t is ... a time period?) but in broad practical terms, the idea of these ready-reckoner tables are that you choose the earth CSA...

please can I get a bit of help in reading table 4.4(i) in the OSG. Is the idea that you simply size the earthing conductor relative to the line/neutral conductors? I dont know how else you would do it but wanted to make sure my interpretation of the table is correct.

please can someone give me a steer on what 543.3.2 is? I cannot find it in my OSG. Context is "Condition and accessibility of main protective bonding conductor connections (543.3.2; 544.1.2) requires further investigation without delay." thanks

when did the familiar 13A plug get half-insulated pins on L & N?

please can wiser people comment on the below: if I ask for an Economy 7 tarriff, will the energy supplier arrange for a new meter to be installed? Does an economy 7 meter come pre-preogrammed with the low rate periods? can I get an aux output signal from the meter to enable me to...

I guess that there might be a period available (when no other switching is taking place) where individual teleswitches could be "stunned" by the LW signal

supply at the property in question is arranged as follows: L1, L2 & L3 are connected into a 3-phase mechanical meter, out of which only L1 and L2 are utilised. L1 energises storage heating via a radio-teleswitch/contactor arrangement. L2 supplies the "24 hour low rate" fusebox which is feeding...

there were (are!) 2 meters - 1 for normal rate, and 1 for low rate. the main low rate load (heating) would energise using the long-wave controlled teleswitch (sometimes via a separate contactor) the 24-hour low rate fuse box would be permanently energised, and metered via the low rate meter...

The supply arrangement in question is certainly full 3 phase & neutral. 400V between the line of all 3 fuseboxes. 400V exists within the single dwelling house. each phase has a 100A cutout. I have done work on the property and measured it myself. and Yes - regarding the "24 hour low rate"...

Yeah, Ive always wondered that too. the "Total Heating with Total Control" branded scheme I think is (was) perhaps peculiar to Scotland and possibly had something to do with a way to use the white elephant of hydro-electric pumped storage in the remote highlands. Im sure others will comment...

I have a somewhat unusal residential supply question for an elderly friend (at least in my limited experience it is unusual) 3 phases entering the house I cannot remember the exact setup of the metering at the property (will update when I visit later in the month) but its something like this...

must admit I hadnt really considered that. most people can certainly feel 24V if you are up to your waist in seawater but it's only uncomfortable, I wouldnt describe it as a shock. No idea what it would be like if you were up to your neck, I guess it could start to become dangerous then. I...