Drop over 3 phases

[rmaynard]

I have installed a 16a 3 phase extract fan, when doing my testing after id finished i had 403v between phases, boss thinks this is ok but i think its a bit low, anyone?

 

[Guest123]

UK nominal voltage is 400/230V +10% -6%. So 403 between lines is within limits

 

[topquark]

If it's consistently between all phases then as Lenny says it's fine. If for some reason you were getting a wide variance between two of the phases it would be a cause for more head scratching.

 

[mechelec]

What is the voltage at the origin of the installation? from this you can determine the voltage drop and wether it is acceptable or not i.e. does it exceed 5%.
it would need to be 424 V at the origin or more to exceed 5% on the voltage you have given. Another deciding factor is what the manufacturers instructions say is the minimum limit.

 

[Guest123]

Seems i may have grabbed the wrong end of the stick and ran with it fir all it was worth.

Are you saying your 403V was measured at the 'load' end of your new circuit, under load???

 

[rmaynard]

Its at the load end but not under load, 413v was at the supply end

Sent from my GT-P1000 using Tapatalk

 

[netblindpaul]

A 10V drop with no load?

 

[mechelec]

A 10V drop with no load?

if that is correct I would want to chech the normal running voltage at the fan terminals as you may find the voltage drop exceeds 5% and someone has got their calculation wrong.

 

[rmaynard]

the problem lies in the use of cable already present, its a 2.5mm multi core 10 with 5 cores being used, IR was sound >299 , just money saving by the boss

 

[Engineer54]

Well, ...you could always use the other unused cores by paralleling them. At the very least it will keep you under the 5% voltage drop limit!! lol!!!