Volt drop, why do we bother?

[La Poste]

Looking at the regs it says we have a supply of 230 Volts and so we do our calculations based on this so that if we had to install lights on the end of a long cable we would use a cable with a larger CSA and hence more cost.

The fact of the matter is we have a supply of 240 Volts so why do we bother?
What is the point of installing these larger cables when there is no need for them, no need at all?

Thanks for reading.

 

[Sparky Ninja]

Supply voltage isn't and constant, and voltage drops over length, resulting in effect in voltage across the load.

Seems a no-brainer to me?

 

[La Poste]

I have never found a supply voltage of 230 Volts.

 

[Sparky Ninja]

I have never found a supply voltage of 230 Volts.

Hence my "not a constant" remark.

I bet you rarely get exactly 240 V either.

 

[GLENNSPARK]

voltage will fluctuate...it will depend on the impedences of supply cable/s and other loads on the ringmain/string...

 

[La Poste]

Ok so we are basing our volt drop on worst case scenario?

230 volts being the figure given because we are assuming the supply is under a heavy load from other consumers?

 

[Ponty Massive]

Ok so we are basing our volt drop on worst case scenario?

I'd agree with that.

 

[dichroic]

Having a voltage drop higher than 3% is not necessarily a safety concern, but rather a performance concern.

In the appropriate circumstances, finding out voltage drop is a wise first step because low voltage has many negative consequences, such as wasted energy in the wiring system. Wasted power is commonly followed by poor operation of electrical equipment, among other problems.

Determining voltage drop is essential, since not doing so could be detrimental to the life of your equipment.

Dichroic

 

[GLENNSPARK]

Having a voltage drop higher than 3% is not necessarily a safety concern, but rather a performance concern.

In the appropriate circumstances, finding out voltage drop is a wise first step because low voltage has many negative consequences, such as wasted energy in the wiring system. Wasted power is commonly followed by poor operation of electrical equipment, among other problems.

Determining voltage drop is essential, since not doing so could be detrimental to the life of your equipment.

Dichroic

not just that....you might find stuff not working at all....lamps not striking etc....

 

[telectrix]

obviously, then these lamps need to join unison.

 

[habitual]

Whilst supplies are now currently running at 240 v, the DNO's are in the process or should be of improving and stabilising the supply voltages to 230 v +or - the accepted variations. Unfortunately we have to design circuits to the guidelines presented, therefore all our calculations are based on an agreed supply voltage of 230 v

 

[La Poste]

I am also thinking we use 230 Volts because eventually the DNO's will drop the voltage, that's my understanding of it.

 

[habitual]

Yes it was agreed some time ago, but as yet still has a long way to go, just like the requirements for making all TN-C-S installs PME, its going to take time, but we poor electricians have to do our job when clearly the DNO's are lacking in their duties.

 

[Guest55]

Why ?
because the big green book of electrical fun tells us to.

 

[Guest55]

And any mere mortal that questions this will be struck down by furious vengance and lightning.
so i've been told anyway.

 

[telectrix]

at the end of the day, all design calculations are erroneous, because they are based on a virtual voltage, not a real one. why do we bother?

 

[La Poste]

at the end of the day, all design calculations are erroneous, because they are based on a virtual voltage, not a real one. why do we bother?

Is that that all or virtually all design calculations? :sultan:

 

[habitual]

at the end of the day, all design calculations are erroneous, because they are based on a virtual voltage, not a real one. why do we bother?

I have always had a problem with this, just like you are saying, however there has to be a national standard, and a starting point for design, it was decided some 10 years ago to go with a standard voltage of 230 V, since then all designs have been based on this voltage. The problem we have is the supply companies make more money supplying higher voltages and are reluctant to conform.

 

[La Poste]

The problem we have is the supply companies make more money supplying higher voltages and are reluctant to conform.

Why is that, why do they earn more?

How come?

 

[ipf]

at the end of the day, all design calculations are erroneous, because they are based on a virtual voltage, not a real one. why do we bother?

That's my wage down the pan then. Ah well, there's always plumbing......then again that's virtually brainless anyway.