Hi Guys,
could anyone explain to me the 1.2 volt drop rule of thumb? i understand the 3% for lighting and 5% for other circuits.
any help would be welcome studying for 2391.
Thanks in advance.
is this right
mv on chosen cable from regs x length of cable run x design current of circuit
divided by 1000
is it calulated amps or the breaer your going to use
is that all as im trying to work out for this lighting circuit but to get the volt drop under 3% the cable needs to be 6mm
ta...
I am currently designing a 29kW system for installation on an agricultural barn.
The PV system will feed into a 3ph db in the barn. The exisitng db is fed from a 63A fuse switch, approx 50m away with a 16mm cable. The fuse switch is in turn fed from the DNO cabinet approx 100m away with a 35mm...
paulsamuel1984
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When calculating volt drop on three phase, I can't remember if I my calculation is using the total current on all three phases or just each individual one.
So each phase at 400v is 3.8A. My calculation was 2.5mm minimum. A three phase motor run in SWA. The run is 200M underground.
SimpleSimon
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hi
i have a long cablrun of 500m for a entry gate which possible will have a worm drive so current usage will be low.my question is i have to supply a 13A socket for remote working ect,this socket as not being used constantly should i calculate VD on the 13A which will be used 1 a year are on...
I have a run of garden lights to wire up, roughly 1000w so about 4.3A. If they are on an rcd spur from the ring main, is the volt drop allowed for a lighting circuit (3ish %) or for ring main (7% is it)? As 100m at 4.3A will require 4mm if my calcs are correct for a 3% Vd.
adam.h
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done a quick excercise to give a rough guide. each cable is assumed to be carrying it's max. load, clipped direct, to give worst scenario, and a 10m length of cable. so the figures below represent the worst volt drop/10m
1.5mm ...5.8v
2.5mm....4.86v
4.0mm....4.07v
6.0mm....3.43v...
whats the reason we worry about volt drop?
It cant be because of the design of fittings etc.. because the actual voltage can be 230v +10% -6% percent,
i believe if there is a voltdrop then the current will increase as per ohms law
maybe its something to do with potential differences e.g...
bobbybrown
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hi all i have been to collage today and we did a bit on volt drop. can some one plase help explain this to me? does this mean on a long run if the cable is not big enuf it will loose volts? eg. 221V?
james king
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Greetings.
I have a question, this has been puzzling me for a while.
If a put an earth rod in the ground and use it as my main earthing method and measure the resistance I find it to be 160 Ohms.
Ok, Assume there are no RCD's and a link is made between the phase/line and earth at the...
hi all
got a sud main to price 45A 27m
45A x 27m x 4.4mV/A/M for 10mm divid 1000
VD 5.34V
now some of the circuits on submain are lighting mav VD 6.9V leaving only 1.56V for the lighting circuit.
6A x 20m x 44mV/A/M for 1.0 divid by 1000
VD 5.28
now am i right to say this sub main...
Any explanations on how this is calculated ?
Diversity :
By referin to table 1b in the osg, it states : 100% largest motor ?? ...3kw ....???
3000/230 = 13.04 A....is this it !!?? max demand ??
How there on would you make cable selection , mcb selection ?
daiplayer
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Can anyone tell me where I'm going wrong.....
Common knowledge 100m is max for ring final!!!!
Im trying to work out volt drop for said length and I am way off where I need to be.......
singles/trunking............15x32x100/1000=48v
Yet if I put a radial in ....15x16x100/1000=12
Can anyone...
LJC
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Hi Guys
I have a question regarding volt drop.
Some time ago a company I worked for installed wall mounted aircon units around their workshop. They wired them into an existing 2.5mm ring main circuit which was in singles in a truncking. During operation some of the units would cause the...
I've yet to come across this problem but like every good scout I like to be prepared.
If a circuit is over the maximum volt drop permitted but fixed in the length of the circuit, how would you over come this? Would it be a simple case of using cable with bigger csa? Does anyone else know of...
1. Discharge lighting is on a 16A mcb, can it stay this way or will it need to be updated to RCBO for the new regs?
2. Radial sockets 50 metres away, on 32A RCBO, wired in singles, in trunking and conduit.
What size cable should be used taking voltage drop into account?
3. 3 phase motor...
ta-electrical
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hi im struggling with volt drop , the circuit is 6mm 2core swa , run under ground , 220M long ,supplying a transformer charging batterys for a gate system rated at 5A.
Can anyone help me and give me the formula for the calculation? Thanks:confused:
f1ngerz
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