Maximum Demand & Ib Design current

[madmatt]

Hi I have not had to work out max demand for an install or design current for donkeys and now my mate is needing some works in his shop and I can't remember the way to work it out or find my old college work ! also .....

Does anyone remember how to work out the volt drop calc for the mV/ per amp/ per metre carry on ?

Thanks, Matt.

 

[Guest123]

VD = (mV/A/m) x L x Ib / 1000.


The mV/A/m value for the cable in question you will find in BS 7671.

 

[madmatt]

Cheers Lenny, the values in the regs bit is fine but it's the design current Ib I can't remember or how to calculate maximum demand, already got the diversity percentages in the on site.

 

[Sintra]

Hi I have not had to work out max demand for an install or design current for donkeys and now my mate is needing some works in his shop and I can't remember the way to work it out or find my old college work ! also .....

Does anyone remember how to work out the volt drop calc for the mV/ per amp/ per metre carry on ?

Thanks, Matt.

Maximum DemandCurrent demand to be assumed for points of utilisation and current-using equipment
Socket-outlets other than 2A socket-outlets : rated current2A socket-outlets : at least 0.5A
Lighting outlet : connected load with a minimum of 100w per outletFinal circuits for discharge (flourescent) lighting : rated lamp watts x 1.8
Electric clock, electric shaver supply, bell transformer, current using equipment of less than 5w : may be neglected
Cooking appliances : the first 10A of the rated current plus 30% of the remainder of the rated current plus 5a for any socket outlet incorporated in the cooker switch
All other stationary equipment : British Standard rated current, or normal current
The information and values given here are for guidance only.

 

[Exploder]

yes voltage drop = cable length * design current * (mV/A/m) / 1000 . The values should be within 3% for lighting and 5% for eveything else..

Hi I have not had to work out max demand for an install or design current for donkeys and now my mate is needing some works in his shop and I can't remember the way to work it out or find my old college work ! also .....

Does anyone remember how to work out the volt drop calc for the mV/ per amp/ per metre carry on ?

Thanks, Matt.