Search results

Hi, have problem Currently a metal DB with failing RCD installed 3 phase TT supply Need to change DB for Double insulated IP rated with 100A 100mA TD RCD Problem is .... a time delay RCD trips with 0.13s-0.5s but under 17th edition, it must trip 0.07secs as i understand from Table 41.1...

Does anyone know where i can find Practice exams for the C&G 2330 (1st Year) course The exams relate to health and safety in work place and also a little technical knowledge. Any practice exams related to the subject and same difficulty region would be appreciated thanks

sorry for more Part P topics ... Does Part P only apply to domestic buildings ? want to add switched fuse spur to power circuit, to feed outside light at a commercial building

On tests sheets when you fill in maximum disconnection times allowed ... 5 Secs for lights etc non-portable fixed equipment 0.4 secs sockets supplying handheld equipment 0.2 (200ms) - for 30mA RCD protected circuits, sockets that could easily supply outdoor portable equipment Is...

This should probably be in another place on forum, but wanted response from electricians... sorry At work we have a Megger/AVO CM500 , which is pretty good tester in my opinion. It tests earth loop with just two probes (no neutral needed) ...only prob is we need another tester and the CM500...

What should be done in the following scenario.. ? two shops divided by a wall.. "Shop A" 3 phase 100 amp TNCS "Shop B" single phase 100 amp TNCS The wall was knocked down making just one Shop with 2 TNCS supplies. Both Shops had a seperate water main, but now, "Shop B" water main...

If i have 16mm2 two core SWA ... how do i determine the CSA of the steel armouring ? a) would it have the equilvalent current carrying capacity as the P+N conductors ? ie 60amp copper - 60 amp steel armour b) would it have the same CSA ie 16mm2 copper therefore 16mm steel wire c) or...

I know how to carry out the test, but i am not sure i understand the reason for carrying it out... some ideas of mine are ... R1+RN could be used to calculate PSCC ? A high R1+RN would signify spurs/alterations to the circuit ? "rn ring continuity" doesnt actually confirm there is a...

If i have an installation with no water, gas services ... then there are no equipotential bonds in place .... would this still count as EEBADS as the method of protection again indirect contact ? If EEBADS is not correct, then what would be ? :oops: EADS - earthing and automatic...

If i have... 3 phases 70mm cables 120 Amps BS88s ....feeding a busbar chamber and then coming off the busbar in 25mm, single phase, to feed a switch fuse of 60/80/100 amp rating ... all run in steel trunking, all singles cables, all cable entries protect cables with paxelin(spelling?)...

Is it possible for overlapping earth fault paths to trip RCDs ? Two houses next door to each other, both TT systems One house has a fault which passes to earth, and it trips an RCD in the 'other' house ? Possible or not ? if yes, could you explain how it works? Thanks

If i have a Semi enclosed fuse of 30Amp for example, how do I calculate the maximum earth fault loop impedance that would allow the breaker to operate in the specified time 5 seconds or 0.4 of a second ? Looking at the Regs they give you tables and graphs, but they also say these values...

if your earth loop is too high for the device, how can you fix the problem ? upgrade Earth conductor CSA upgrade live conductor CSA or, change the device for one which trips easier any other ways ? We got a problem after a test was carried out on a school... A fuseboard is supplied...

I remember reading that you are supposed to test circuits before carrying out work on them (extending them etc)... (?) is this in regs or anything or just guidance or am i off the plot ?

Had a problem where the neutral had came out in the consumer unit - which destroyed alot of things on certain circuits I was wondering why this happens, since if the neutral is out then it breaks the circuit - so current doesnt flow is it voltage build up in the cable and appliances ? or...

Hi ... Got vauxhall Astra and just put a new stereo in it Does anyone know which colour wire is for the memory, which stores the radio preferences ? ... Would be useful since then dont have to tune in radio everytime i start the engine Thanks