2% & 3% Voltage Drop in Florida

[BRYAN AMBROGIO]

It used to be 5% total voltage drop, then it was 2% for feeders and 3% for branch circuits. I cannot find a reference to this in NEC. I did find a reference to this in the Florida Building Code for 2010 and 2014, however, per 2017 FBC it appears it went back to a 5% total and they removed the 2% & 3% rules. Can anyone please tell me is there currently something in NEC, FBC or any other codes that still require the 2% & 3% rule in Florida or has this rule gone away?

Please Advise...

Thank You

Bryan

 

[PD1972]

The 2% and 3% voltage drop for feeders and branch circuits respectively is not a requirement of the NEC. Based on the 2017 edition of the NEC, references to 2%/3%/5% voltage drop are only found in informational notes (210.19(A) and 215.2(A)(1)). Informational notes are explanatory in nature and not enforceable so the NEC does not require you to adhere to the 2%/3% criteria. The NEC states as such in 90.5(C).

As you noted, there is a requirement for voltage drop for feeders and branch circuits in the energy conservation portion of the FBC. The currently adopted 2020 FBC states 5% total voltage drop for commercial buildings.

It appears that, as you suspected, the 2%/3% rule in Florida has gone away and been replaced with 5% total.

 

[BRYAN AMBROGIO]

thank you

 

[tom baker]

There is a voltage drop requirement for fire pumps in the NEC. You end up paying for excessive voltage drop in conductor heating