1. M

    Convert 3 phase into 3 single phases

    Hi there, I have currently started working on a farm and they are having a new 100a 3 phase supply installed. This is being terminated in an external enclosure. They then want to carry this 3 phase 150 meters to a barn and at this point split it into 3 single phase supplies. Is this even...
  2. L

    Industrial There is a one circuit (one voltage source), two phases and neutral, but there is an amps difference between Ph1 and Ph2 (minor 3A only).

    Hello Electricians, This is my first post and I'm glad to be one of this forum member. However, to clarify my question. I've a "Skin Effect Heating System", fed by 1240 V. The circuit is quit simple, Phase U, Neutral in the middle and Phase V. Phase U and Neutral feeding the heating cable#1...
  3. MarkRibbands

    What colour panel lamps to indicate phases?

    I’m making breakout (‘Distro’) boxes to distribute power from three phase sockets in my workshop to clients’ temporarily-installed single phase equipment. My question, given that I want to have pilot lights on the boxes to both confirm supply and to indicate from across the room which sockets...
  4. D

    Single phase board use with 2 phases

    Hello guys new in this forum. In my 19 years as an electrician I've never seen this. Looking for any thoughts on this. Been asked to install a few new circuits In a domestic garage. There is a granny annex on top of this garage also. Supply is 3 phase in to a 3 phase isolator. From there...
  5. MarkRibbands

    Timer and local thermostat control of 3 x heaters on 3 phases. Wiring logic help please!

    I'm fitting oil-filled panel heating into two rooms of a remote workshop, with (currently) a 20A x three phase supply. Control, for occasional use only, is needed as follows: 1. A wall-mounted and easily-adjustable mechanical timer to set all the heating to come on an hour or two before people...
  6. MarkRibbands

    Three phases in single domestic kitchen grid box. OK or not?

    I'm fitting a small kitchen in my remote office/workshop with a limited, existing, supply (3 phase/20A MCB on a long 4 x 10mm SWA). I need to think carefully about diversity and load balancing. My proposed solution is to install individual final circuits for every appliance (Small hob, Small...
  7. G

    Neutral between phases

    I am trying to connect a smart light switch but there is not neutral. Next to the switch there is a socket with a neutral but it is under a different phase. I understand that it is the same neutral for the whole house on all phases, but when I use the other neutral, it short circuits. I checked...
  8. C

    3 phase supply to single phases only 2 phases used

    I went to some holiday cottages today, the main supply in was 3 phase however only 2 of the phases were used. The L1, L2 and Neutral cables were wired into a three phase meter, then coming out was L1 and Neutral, L2 and Neutral to create two single phase supplies which were divided off using...
  9. D

    Industrial Three phases main supply

    Where i can find in the regulations that the always has to be L1 - brown L2 - black L3 - grey
  10. G

    Can you take 2 phases to a consumer unit?

    Hi, I am training to become and electrician, I have passed my C&G level 2 exams. I am working as an electrical improver. I came across a consumer unit today, which has two main switches and two phases L2 and L3 supplying it. Does this board comply with regs? Can you take 2 phases to a...
  11. S

    Phases in dado trunking.

    Hi all and thanks in advance for any replies. I was wondering if whether when having more than one phase inside a dado trunking are you required to mark up the trunking with a 400v marker/label like you would at a multi gang light switch?? Cheers
  12. E

    2 phases and neutral

    went to look at a job this evening and the supply into the building is 2 phase and neutral. They property is a shop ground floor and a flat on the first floor, one phase for each unit, my guess this is the reason for the two phases, but why not bring in all 3? I haven't come across this before
  13. T

    3 phase pump

    Hi All i have 3 phase pump set on a primary chilled system for which i had a quick look at a few days ago ive given a quote to look at as its not running for love nor money, ive only spent 10 minutes fault finding but something doesn't add up, its 3 phases and earth no neutral, im getting 230v...
  14. Michaelwgroves

    Multiple Occupancy Buildings

    Hi, UKPN are installing a new 200A 3PN supply. Their incoming cable is 95mm. As per the Multiple Occupancy Building recommendation G87 they will only supply the cut out. I now need to supply an isolator and Ryefield (or equivalent). Looking at table 4D1A 70mm cable will cover me for free air...
  15. E

    small building site temp distribution

    I am setting up some temps on a small site consisting of approx 3 110 transformers 2 portacabins offices sitting on top of each other, a portacabin toilet and a portacabin drying room. The supply is a 3 phase DB. Im thinking use 1 phase for the trannys, 1 phase for the offices and the other...
  16. W

    Domestic three phase with single phase PV - net metering

    Another family member had a number of eco features added to the home when built a few years ago. This included a ground source heat pump, hence the three-phase, and solar PV. I had a look at the setup recently and observed the solar PV is single phase. Furthermore, it is on a phase with one...
  17. A

    currently 2 phases in venue unable to upgrade to 3 phases

    Hi looking for some advice I am about to start a commercial job in a rural area the venue is being totally renovated it is a 30 bed hotel which is being extended will have 2 bars large function room a large commercial kitchen and a spectate motel in the future. The venue is only supplied on 2...
  18. charlie76

    What are your thoughts on this 3ph domestic.

    The installation on the attached pic is a property with a 3-phase supply and a range of fuse boards. I am currently in training but this is a family friend and I have discussed carrying out a rewire for them once I get my papers. I intend notifying the works to BC and then getting NAPIT in to...
  19. the pict

    DNO connection team

    What is difficult about this, one building formally a pub,hotel, restaurant, with a 3 phase supply, the property at some time in the past ceased being a hotel but remained a pub restaurant, the rooms were converted in to 2 flats and supplied with one phase each from the existing 3 phases, a...
  20. joel89

    Testing ze at the origin

    Hi all I'm an industrial sparky on maintenance doing my eal initial verification exam tomorrow was just wondering when doing ZE at the origin, do you do Neutral L1,L2,L3 and then Earth L1,L2,L3 and N+E ? Or is there between phases too? And is this the same for The PFC?
  21. S

    2 phase dc to ac converter in a 3 phase house

    I am about to buy a Pv Solar system for my house(Grid tied system ), the system is a 10Kwatt system, the company that is going to install it, is quoting me a 2 phase DC converter but my house has a 3 phase transformer, they said that there is no problem, but i am not so sure, any help will we...
  22. R

    splitting 1 phase of 3 phase supply query

    Hi, I need to split a single phase from a 3 phase supply into 2 separate connections. The 3 phases are currently being used by a shop and 2 flats above, with each using 1 phase. We have put a 3rd flat on top, however believe we can split one of the existing phases so the 3rd flat can...
  23. D

    3 phase meter

    A building has 1 3 phase thing in it and 3 fuse boards single phase 1 to each phase but they are going to turn of one board for about a year . How will this affect the readings as in bills How does a 3 phase meter work
  24. P

    100 A MCCB feeding DB with various RCBO's tripping before they do?

    Hi I have a problem on a site that I have inherited. The fault is that a 100A MCCB is tripping indeterminately. The MCCB feeds a DB which has several cct’s none any higher than 32A and all cct’s are RCBO’s the RCBO’s are not tripping yet the MCCB is. The MCCB has been changed recently...
  25. C

    110v transformer problem

    Was called to look at a 3phase 400/110v 10KVA transformer on a building site. The workers had been complaining their power tools ran slow. Found 230v on all 3 phases and 400v between all phases. Transformer output was 55v between phases. Healthy transformer on floor above, (which was on same...
  26. T

    Insulation testing results

    Hi, Very new to this forum so excuse any faux pas's. Was wondering if anyone has come across this situation: Was doing some insulation testing as part of our planned maintenance and came across a motor that gave an odd result. Capstan Motor 440V/60Hz, 24kW, Star/Delta configuration. Removed...
  27. J

    Separate fuses for 3phase supply

    Hi All, Just trying to double check if there's a reg suggesting a 3phase circuit should have over-current device that disconnects all line conductors at once? Got an old rewireable board supplying 3phase motors with 3 individual fuses. I'm looking at 530.3.1 ................... Can anyone...
  28. G

    Do split phase boards exist?

    Living out in the sticks. I have come across old split phase installations a few times and done a little maintenance on them. These installations usually consist of a old 3 rewireable db with only 2 phases used. Well for the first time I have been asked to add some circuits which requires a...
  29. B

    3 phase to single, and back again...

    Hello. I'm a bit confused with the electrics on an industrial unit I'm leasing. Ideally I'm after 3 phase - there is 3 phase coming into the building (with a 3 phase fuse box), but the previous owners wanted single phase and created a single phase set up from one of the 3 phases. Here's a pic...
  30. Toby Kuhnert

    2 phases in domestic bungalow??

    Hi Guys, Popped over to a bungalow yesterday that a mate of mine has bought to renovate, asked me to have a look at electrics/what might need doing and I found this... 2 phases (red and yellow) in a bungalow with 2 bedrooms?? bit ott i'm thinking? lol. Although the DNO have only supplied a meter...
  31. N

    Max PSCC 1 phase and 3 Phase

    Hi all. Prospective Short Circut Curret. Now , if you measure the impedance on a installation P to N , and get a reading of 0.21 OHMS , the max current flow between these two points P and N will be 230/0.21 = 1095A.....1KA. Now if you have 3 phases , and each are the same impedance P to N ...
  32. F

    2 Phase PV Problem with RCDs

    I have just installed a 2 phase system with 2 Solar Edge inverters (3.7kW per phase) Each pv system is fed through a shared Elster A1100 3 phase meter and each one runs fine on its own. When connected at the same time the RCDs on both system trip. The only way I can make it work is to bypass the...
  33. J

    Different phases for a 13A socket outlet and 5A socket outlet 2" apart

    Hi all. We're currently wiring a large domestic dwelling that has a 3 phase supply. We would like to balance phases as accurately as possible, but due to the lighting control system we have a situation where we have a 13A socket on one phase sited next to a 5A socket on another phase. These...
  34. G

    Shut off 3 phase supply

    I need a solution for a problem I have, just cant seem to think at the moment. I need to shut off a 3 phase supply when a supply to one phase has failed? Now I am thinking 4 pole contactor, but I am not sure of how to monitor the 3 individual phases on 1 control circuit? 3 control circuits perhaps?
  35. G

    Standby generator

    We have some work to do at a large house in the countryside,that has a two phase supply installed .There is a standby generator being fitted next week,which requires conversion from three phase into two phase,by the generator suppliers.Does anyone know if we need two neutral cables to feed the...
  36. H

    Correct warning signs for high voltage (potential belt off 2 phases) please help!!!

    Anyone with experience of this or an idea please help. I have 2 phases going going into a cab, each one 230v. However there is a real chance someone could touch the two and get a belt from each phase at the same time. What would be the correct type of warning sign to use? Also out of...
  37. the pict

    Tri phase board out singles in

    I am doing commercial refurb at the mo, everything is supplied from an old Memshield 3 phase board, the landlord wants the various spaces metered so he can bill the tenants separatly, at present he is just adding a flat rate to the rent, I have no issues with how to go about it however one unit...
  38. S

    G59 Relay

    If we have 3 x 2500wp single string arrays on a 3 phase supply (split evenly over phases) using SMA 2500HF's will we need a G59 relay for sure or is it up to DNO? The SMA's are not G59 as far as I know only G83.
  39. rustynails

    2392 Question - Balanced prospective short circuit current between lines

    The prospective short-circuit current between line and neutral is measured at 900A. The maximum balanced prospective short-circuit current level between lines, as a rule of thumb, can be assumed to be approximately: A: 0.9 kA B: 9 kA C: 90 kA D: 1.8 kA :banghead:
  40. P

    Testing question following successful 2391 result

    Hi all I passed my 2391 about 6months ago and thought I was flying, I know test procedures & how to carry out the tests like the back of my hand and I fully understand any results I get and how to rectify or diagnose any faults in a electrical system.....but then again I have only tested...
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