A "qualified" electrician is refusing the client's request to wire the final ring circuits with 4mm ?
The client ( a friend's son renovating a large property ) on my advice wants to pay for 4mm on the rings to reduce the voltage drop in cables to a minimum. The electrician is stating that as long as the voltage drop at full load is less than 2% the system is correct and any changes will make it not correct.
The electrician has calculated the voltage drop as being just less than 2% so insists 2.5mm is the correct and only cable to use.
As the client says a 2% drop in voltage is 4.6 volts which at full load ( say 30 amps on a 32 amp MCB ) is 138 watts being dissapated in the cable.
Have yet to discuss the 10mm feed to the range cooker.
The client ( a friend's son renovating a large property ) on my advice wants to pay for 4mm on the rings to reduce the voltage drop in cables to a minimum. The electrician is stating that as long as the voltage drop at full load is less than 2% the system is correct and any changes will make it not correct.
The electrician has calculated the voltage drop as being just less than 2% so insists 2.5mm is the correct and only cable to use.
As the client says a 2% drop in voltage is 4.6 volts which at full load ( say 30 amps on a 32 amp MCB ) is 138 watts being dissapated in the cable.
Have yet to discuss the 10mm feed to the range cooker.