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    Calculating power consumption

    I have a 415, 55kw motor running at 30 amps for the best part of 12 hours a day. If i am to calculate the power consumption, what equations would i use; if i use P = 1.73 x 418 (measured) x 30 xPF x efficiency what values would i use for efficiency and PF, i thought these values change...
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    Earthing conductors

    If a TNS installation has 16mm tails, and a 10mm main earthing conductor, would 6mm main equipotential conductors be ok to use (ie to gas, water etc) or would you have to use 10mm as that is what the main earth is?? Thanks
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    RCD Tripping instantly

    Guys Just witnessed something weird and was wondering could you help. Recently replaced a CU in my brothers house that he is renovating. I undertook the rcd tests using an alphatec tester and it tripped in the required times (and not at 1/2) so i was happy that all was ok..... until today...
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    garge wiring

    the gap between the garage and the house is less than 1 metre with the total run not exceeding 5m. I am planing to use 4mm cable (pvc) with conduit running between the two buildings. The mcb is an old type 16a (push button type). Inside the garage is a new rcd unit with a 16a and a 6a mcb...
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    outside power

    friend of mine want lighting in his decking. i was going to run a cable from the cu through to the garage and install a smaller cu for the outside power etc. due to the way the joists are this is impossible without lifting the boards which is not an option. Would you recommend spurring off...
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    Inspection and test

    it has been some years since i took the 2391 exam and i was asked by a friend yesterday to 'see if i need a rewire'. I undertook all the relevant tests, all the cables were new ish but all identified correctly etc. He asked me if he needed a new board as the one he had used fuses, but was...
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    What can be wrong?!!

    Hi, I have recently moved into a house that has just been built and im having problems with the central heating system. The tap pumps out water that is too hot to touch eventhough the thermostat is set at 45 degrees! Secondly, the water is constantly on even though the control panel clearly...
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    TT earth rod resistance

    Any ideas how to test the value of the earth rod resistance, as of yet I do not have the 4 lead meter tht is required. Is there another way?? Was under the impression that if the whole house is under RCD protection (100ma time delay and 30ma split) there would no need to calculate this. Please...
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    Identifying installation type tt??

    Hey guys, looking at a friends house installation that he wants checked out before he has a rewire. Looking at the main supply cable to the house (old terraced house) there are only 2 conductors in the PVC cable (16mm red and black). Looking further there appears to be no earth bonding to pipes...
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    12v between earth and live when switch is off

    Hey fellas, waas wondering if you could help me trace a problem. When i switch off the downstairs socket in a house i have been asked to check, there is 12v between the live and earth pin of the double socket. The swicth is a chrome double pole and all cables are terminated correctlly...
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    Installation test equipment

    I am thinking of buying a new tester, the Alphatek Easitest, has anyone used it and have they any comments to make about it?? Thanks
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    Backplate

    Does anyone know where i can purchase back plates for after market light fittings?? Thanks
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    Dangerous installation

    Lads, I was over my friends house earlier tonight as he has had his house rewired by an 'electrician'- i was looking at a lighting fault. The house has a TT system, with the earth rod on the side wall of the house, the only thing is is that it is not connected to anything, just a 10mm earth...
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    Yet another Part P question

    Lads I work as an electrician in the steel industry and have passed the inspection and testing, 16th edition etc and have been working with a NIC registered electrician when doing house rewires etc. The only thing is is that he has moved away but ive still got to finish a house. I used to...
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    16mm cable

    Any of you had the experience of using 16mm cable for a cooker and a shower? rewiring a house for a friend and they have 16mm cable (dont know where they got it from!) they dont want to spend more than what is necessary!
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    Consumer unit question and main fuse

    The consumer unit i have bought for a house has a 100a main breaker, yet the main supplier fuse is only 80A. Surely this is not right, yet i have been told that this is ok. i have always bought 80A breakers instead. what do you think?
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    LV Lighting

    Believe it or not guys, this is the first time ive used low voltage lighting. Doing a bathroom that has 6 lv lights each with its own 60VA transformer. I have daisy chained them from the first in radial fashion. I have mounted the transformers to the wooden ceiling joists via screws and also...
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    10mm or 6mm

    Guys Does anyone have any preferences to using 10mm as oppose to 6mm, I always used to rewire in 6mm for showers and cookers (depending on cable run etc!), just wanted to know if you have all moved from 6mm and wired in 10mm with the introduction of larger hobs, showers etc
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    earth loop impedance reading

    hi lads, tested an installation yesterday using a robin installation tester (had it about 2 years). testing the external earth loop i had 0.17 ohms (TNS supply) this seemed very low to me as the PSCFC will be near the 2K mark. Does anyone else agree that this is too low??
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    Smoke Alarm

    Hi Lads, i have just finished rewiring a 3 bedroom house and have just completed the test and certification (yes part p b4 u ask!). I have wired the smoke alrm on its own circuit on the non rcd side of the board. just wanted to know does anyone else do this or do you spur off the lighting...
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