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  1. H

    Maximum Current Draw

    Hi I am looking at buying 2 NEC PA653UL projectors to stack them to create 1 projection image, but when looking at the input current specification I am in doubt if this is going to work. The input current specification states that it can draw from 4.5A to 10.2A, which seems unnaturally high...
  2. M

    What is maximum distance I can run 12 gauge wire to a shed?

    Hello, Need some advice. I have a 20amp breaker with 12g/2 underground feeder wire running to an outdoor GFIC outlet. 38 feet from breaker box to where it leaves the house and then 32 feet buried 24 inches deep (no conduit) to the 20A GFIC outlet. So from breaker box to outdoor outlet is a...
  3. D

    UK Maximum demand

    Hi All I am doing my assignment and one of the tasks is to create a fuse board schedule showing circuit breaker ratings any assumptions must be stated with reasoning given. using these circuits calculate the maximum demand of the installation Can someone tell me if it is right So without...
  4. N

    Door shutter rcd!

    Hello I have an oportunity to take one big commercial job! there would be 4 -3 phase door shutter!i think 16 amps socket! should i put rcd on each shutter or one enought for 4 shutter? should i protect the ciruitS by rcd? the cable will run on very high level on the cable tray ! if yes ,where...
  5. K

    Can anyway help with Radial circuit maximum floor area help?

    Hi everyone I am doing level3 design andI have a circuit to design but I have confusion with radia circuit maximum floor area to understand? I have a socket to feed on the design and floor area according to my knowledge is Length multiply width so in that case it exceeds 75 m square so I am...
  6. S

    Maximum Service voltage of ACBs(air circuit breakers) .

    Can we use a ACB rated for insulation level of 1000v, and 690 volt serivce voltage at, 800volt. For example ABB sace E1.2N , Can it be used at 800volt AC?
  7. C

    Maximum Disconnection Times

    What is the reasoning behind having a 0.8 disconnection time for up to 120 volts Uo, but it then jumps to 0.4 seconds as soon as you go over it? Wouldn't it be better 0.8 seconds for 150 volts Uo and under, 0.4 seconds 150 volts and over Uo?
  8. ThatMatt72

    UK Can't get within maximum load when applying diversity

    Hi all, I wonder if you might chuck in your 10 cents worth on this on? I have been asked to install electric heating in an office up on the 4th floor of a building. I've looked at the layout of the room, with regards of seating etc and after consulting with the occupiers have decided on the...
  9. Michael J

    The maximum value for Zs on a TT system is 50/I delta. So for a 30mA RCd is 1667 ohms

    why is this not the case if the final circuits on a TN-S or TN-C-S system are protected by a RCD? Funny what you think of when you can’t sleep
  10. dc-electrix

    Maximum demand and diversity electric flat

    Hi All, Making some alterations in an existing flat and scratching my head about required supply to flat. It is all electric, 1 bed, 1 bathroom. Electric shower 9.5kw Instantaneous Water Heater 9.5Kw Cooker Oven & Hob 6Kw 1 Ring main 3 Electric Heaters...
  11. D

    Maximum Luminaire Weight Supported by Plasterboard Ceiling

    Are there are any regulations/guidance on the maximum weight that a luminaire can be if it is only supported by the plasterboard ceiling and not fixed to any joists or noggins? I have a customer who would like a (heavy, but currently unweighed) light fitting from their old house fitted in the...
  12. gazdkw82

    Maximum Zs values for BS3871

    Where can I find the max Z's value for a BS3871, type 3, 32A MCB? Iv had a look through BS7671 and done some searching online but I cannot find it. IV found some tables with listed Zs values for a 3871 but I have no idea where they originate from or how old
  13. F

    Maximum number of lighting points

    Hello, Could any Irish members on here either tell me the maximum number of lighting points permissable on a circuit? I seem to remember a Fàs teacher mine saying that it was 10. The reason being that it's to do with a property being put into darkness in the event of a fault. I also think that...
  14. M

    60947-2 mccb maximum zs

    Can't find any data on these mccb if anyone has the ia for 60a,62a,80a,125a or 250a please post . Pete 999 am looking at you
  15. littlespark

    Maximum load across both sockets of a double socket

    We've had this discussion before, but does anyone have any idea what load can be put through a double socket? The socket in question is an MK logicplus, installed in a commercial kitchen. The supply cable is 6mm, converted from a previous cooker circuit to a double socket. (information gathered...
  16. S

    Maximum Zs on Circuit details schedule

    hi guys, Seen on the circuit details schedule in a DB on our site, someone had inserted Zs values for the circuits as follows. 16a C type breaker as 1.44 ohms 10a C type breaker as 2.30 ohms 80a C type breaker as 0.28 ohms I believe he’s calculated Zs by doing (in the case of 16amp c...
  17. T

    Ze at its Maximum Measurement

    If the Ze on a TNS supply is measured at 0.8ohms, is this still acceptable? Technically it is bang on the maximum. DB is 100A Main Switch with 30mA RCBO's on all circuits.
  18. G

    maximum residual current RCD

    Hi Everyone, I would like to confirm a question I saw the other day regarding working out the residual current on an RCD The question was similar to the following An earth electrode has been measured and the following readings were taken 1) 21 Ohms 2) 21.02 Ohms 3) 20.8 Ohms What is the...
  19. Y

    Maximum Current Capacity

    How much current capacity can handle in a 16 sq. Mm. Wire size in ac 415 volt supply? Because i have 2 pump motors that will connect to a power source of 415 volts ac 3 phase; 1 motor is 5.5kilowatts and another one is 7.5kilowatts. Both motors will run intermittently and supplying different...
  20. T

    DCP 161 implementation April 1st and calculating KVA, maximum demand

    I have alluded to this in previous threads. The commercial site I work on has asked me what I think the total KVA for the site is. Having looked at various ways of viewing this I am getting lost with it. So if I just say kVA = ( V*A*1.73)/1000 and assume supply is 400V and take the main incomer...
  21. B

    Maximum age of wiring

    Hello, I live in a house where part of the wiring dates to 1960 (exact). Now I know after ~30 years old, a rewire is advised. And at 58 years it should definitely be rewired, but it's going to be difficult to convince my parents to have the house rewired soon - as we have 5 people living here...
  22. E

    maximum allowable height for scaffold tower?

    really trying to get the customer to see sense, they have supplied scaffold tower for lighting replacement about 5metres off the ground, which i have been pottering away at with this shitty scaffold tower getting stuck in the sand below and hitting against the beams of the shed itself almost...
  23. G

    Help with Maximum Demand needed

    Hi, I am studying to become an electrician. I got a question wrong on a practice test. Can anyone help me understand maximum demand. this is the question I got wrong..... Question 27: With reference to the nature of the supply, which one of the following can be determined by calculation...
  24. A

    Maximum distance between collectors and tank?

    Hi, I'm looking at installing a solar water system for a friend. He runs a B&B so has much higher hot water needs during the summer, and also a very high annual bill for heating and water. So it seems like he's ideally suited for a solar thermal system to at least reduce the costs. We live in...
  25. W

    Zs ohms with maximum rcd ohms

    If the maximum zs is okay up until 1667 ohms protected by a rcd why do we care about maximum disconnection times for the mcbs e.g why do we test and it's important to meet 1.37 or 1.1 zs on a 32 amp circuit
  26. J

    28A in 4mm cable 6.5kw hob

    i need to wire in an induction hob which is 6.5kw and the cable already chased in is 4mm and would be a real pain to replace for a bigger. I just wanted to know if it would be alright or play it safe with a 6mm?
  27. S

    Maximum breaker size for DB (solar PV)

    Hi, Can anyone point me in the direction of the regulation / code for the max solar MCB size when connecting into a spare way of a local distribution board ? Eg. Is it possible to connect a 100A breaker into a 100A board ?
  28. Cadgey123

    DNO maximum demand message.

    Just started doing my first block of flats as a Qualified supervisor. I have 5 flats and a landlords supply to wire up. Done my calculations a while back and told the DNO I would need require ADMD of 12.5 kva for each flat which I thought was reasonable, Considering I have 3 rings, 2...
  29. L

    R1+R2 Values

    Hi all, Quick question when doing r1+r2 testing wether its a new install or a EICR, is there a table to show maximum readings we should be getting? Or is it a calculation? Thanks in advance Luke
  30. G

    Breaking capacity of 3871 fuse lower than pfc?

    i have just done a test on a property and the pfc at origin of installation was 0.712ka. The 3871 mobs have a 6000a breaking capacity. I am a bit confused as I have read something about it always being higher anyway (16ka) for a fuse or main switch 100a or less. Any info here would be much...
  31. J

    calculating total consumption for each of the circuits and final maximum demand curre

    I have to calculate the total consumption for each of the circuits and state the final maximum demand current. downstairs :2 fittings with 5x 12w lamps,1 fitting with 5 x 12w 1 fitting with 10 x 12w,1 fitting with 1 x 60w,1 fitting with 7 x 20w 2 fitting with 3 x 20w,1 fitting with 4 x 30w and...
  32. J

    TT system with No RCD

    Been out to replace an oven on an installation which pre dates the need for RCD's so only has MCB's, the earthing arrangement is TT. As I am only changing the oven this need not be RCD protected but is the maximum Ze still 200ohms?
  33. G

    Domestic Underfloor heating Controller

    The underfloor heating controller says it will be able to pull a maximum of 16 Amps. The supply is from a 20 RCBO. 2.5mm Twin and earth to a 13 Amp switched fused spur. The load side of the spur feeds the underfloor heating controller. The owner is saying that if for what ever reason the...
  34. Scuba

    What's the largest size array for a 60 amp cable head fuse? Single phase.

    SP Networks are the DNO. Smallholding with single phase and 60 amp cable head fuse. What's the largest size likely to get approval?
  35. B


    Hello friends, i have been doing EICR for caravan sometimes now. On 16A or 32A hookup box with 30maRCD protection mostly found 1ohms or more Zs at hookup and more inside the van. When you put the results in schedule of test sheet which will not comply with maximum Zs value table from regs book...
  36. D

    Fluke Meter Pass/Fail Indication?

    Hi I have a Fluke 1653b and it claims to have Pass/Fail indication on RCD's ?? Where? Is this on the auto mode? I can only get it to auto test then I have to scroll through all the measurements. There is no mention of this feature in any of the manuals?? Help!!! Thanks
  37. D

    transportable building periodic certs

    In section K of the NICEIC periodic certs, how do you find the MAXIMUM TOLERABLE UPSTREAM IMPEDANCE [ZT] donny
  38. S

    MAXIMUM DEMAND... nic assessment

    hi guys. if i calculate maximum demand like i got 6 circuit 32a cooker 32a upstairs ring 32a down s. ring 20a,radial 6a upstairs light 6a down stairs light get the higgest one and add the rest together get 40% of it and finally add to highest one.. do u thing is that right?? and also do...
  39. S

    AC Circuit Theory Maximum Power Transfer

    Hello All, I am currently hitting a barrier with regards to the basics of this question. It is for a HND so I may have put this in entirely the wrong forum. Apologies if so. A 50HZ supply is connected to various given impedance's connected in series and parallel. Calculate the value of the...
  40. J

    little help with volt drop calc

    Hi everyone just a little confused,when calculating volt drop using table 4Ab do you measure the voltage of the installation and use that value to calculate or do you just use the 230 volt value
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