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volt drop
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In electronics, voltage drop is the decrease of electric potential along the path of a current flowing in a circuit. Voltage drops in the internal resistance of the source, across conductors, across contacts, and across connectors are undesirable because some of the energy supplied is dissipated. The voltage drop across the load is proportional to the power available to be converted in that load to some other useful form of energy.
For example, an electric space heater may have a resistance of ten ohms, and the wires that supply it may have a resistance of 0.2 ohms, about 2% of the total circuit resistance. This means that approximately 2% of the supplied voltage is lost in the wire itself. An excessive voltage drop may result in the unsatisfactory performance of a space heater and overheating of the wires and connections.
National and local electrical codes may set guidelines for the maximum voltage drop allowed in electrical wiring to ensure efficiency of distribution and proper operation of electrical equipment. The maximum permitted voltage drop varies from one country to another. In electronic design and power transmission, various techniques are employed to compensate for the effect of voltage drop on long circuits or where voltage levels must be accurately maintained. The simplest way to reduce voltage drop is to increase the diameter of the conductor between the source and the load, which lowers the overall resistance. In power distribution systems, a given amount of power can be transmitted with less voltage drop if a higher voltage is used. More sophisticated techniques use active elements to compensate for excessive voltage drop.
Hi, Thanks in advance for any advice!
I was called out to a client’s swimming pool, as there was a fault on the pool lights. I found that someone had installed 2 x 12 volt 300 watt lamps, recessed underwater into the pool walls, using 10mm cable in parallel so that there are 2 neutrals and 2...
the little boys on here worry about a bit of volt drop a few volts
it happens all over the world children
what the heck wrong with with a bit of volt drop?
things still work thats all that counts
Ok I have another VD question. I'm installing 9 LED floods around my friends garden which totals at just over 100m in length. Obviously for each branch the VD varies so for argument sake I worked It out as if all the cable would be taking all the load (rather than dropping relevant current after...
Hi all,
Just wanting to clarify regarding volt drop.
Client is looking to add lighting to garden, to be supplied from 13a FCU, load on FCU will be less than 1A due to LED lighting.
The FCU will be an addition to a final ring circuit which serves dining room and lounge, protected by 32A MCB...
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I'm having another one of my crazy thought processes that I'd like help clearing up please. This example is completely hyperthetical so please give some consideration for that. If for example a circuit was designed very badly and a length of 1.5mm t+e was used for supplying a 8kw shower and the...
It states that you are allowed a permissible volt drop of 3% for lighting circuits and 5% for power circuits in domestic use. Now is the limits for the entire electrical installation? I was under the impression that it was per circuit. For example 3% of every lighting circuit and 5% for every...
I'm installing a gate supply at the end of a customers garden. My plan is to spur off internal ring main and run a radial roughly 100m to end of garden. Providing the long run cable is of adequate size to sustain 230v to the end of the garden am I right in thinking that I can tee off again at...
How do u calculate the design current on circuit.?My old Qs always used to just put the mcb rating into the equation...
And he once made us wire a 6mm radial for some sockets because it was a long run and he took the design current as 32 a?? It's too difficult to even get the conductors in the...
Hi,
Looking to supply power to two outbuilding/sheds to be used as offices (no electric heating required). one is 60m from supply source and another is 10m further on.
I'm currently debating what size supply / cable to install taking volt drop into account.
Ideally in unit 1 i'd have...
posters on here often worry about volt drop, whats the prob with a few less volts @ the other end of the cable? will a few volts less end in disaster? will the suppy cable catch fire?
be nice i,m mellowed out at the moment:mickey:
Hi,
Looking to supply power to two outbuilding sheds to be used as an office (no electric heating required). one is 60m from supply source and another is 10m further on.
I'm currently debating what size supply / cable to install taking volt drop into account.
Ideally in unit 1 i'd have
-16a...
Is there a noticeable volt drop on the output of wind turbines that would prevent them being situated too far from a dwelling?
Reason I ask is that my my parents declined a wind turbine ( to part supply a 3 bed detached house) as they were told that it would have to be located adjacent to the...
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
Hello,
I seem to be getting a bit confused here and wonder if anyone out there could give me a bit of help.
I am wiring a new build in North London. The Architect is also the client and he is putting some pretty funky and complex kit in the build.
The house has large shutter over the windows...
Hi guys,
Looked over some previous posts and done some further reading, and attempted the calcs, just want to check that i am not miles off the ball park here with this. From what i have read harmonics and current down the neutral will cause massive fluctuations in results not to mention...
Ok you do all your calculations to determine your volt drop and your calcs come back that the volt drop is just above the 5% allowed ok I no it dosnt conform to bs7671 and you should increase the csa of the cable to next size up but what effect or could some one explain in simple terms the...
Pricing up a job in a factory and have to wire in a 3 phase supply, just going to double check my cable sizing i calculate i need to use a 10m cable
Swa cable clipped direct on its own , 35m run feeding a unit needing a 3 phase 20amp supply am i right ? just seems a little on the heavy side ?
Hi,
I need to take a Supply from a house CU to an outbuilding which has a 20A radial socket circuit and 6A lighting. The cable run to the outbuilding is 20M then the lighting circuit inside the outbuilding is approx 10M in length and the socket cicuit 15M in length.
I'm trying to calculate a...
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