# What voltage drop is allowed on a branch circuit?

## What voltage drop is allowed on a branch circuit?

The NEC recommends that the maximum combined voltage drop for both the feeder and branch circuit shouldn’t exceed 5%, and the maximum on the feeder or branch circuit shouldn’t exceed 3% (Fig. 1).

### What is NEC code for voltage drop?

NEC 210.19(A)(1) Informational Note No. 4 limits the voltage drop at the furthest outlet of a load to 3% of the applied voltage. This allows 2% drop in the feeder. Alternatively, the maximum combined voltage drops on the feeder and branch circuits going to the furthest outlet of a load should be limited to 5%.

#### How do you find the voltage drop in a branch circuit?

To calculate voltage drop:

- Multiply current in amperes by the length of the circuit in feet to get ampere-feet. Circuit length is the distance from the point of origin to the load end of the circuit.
- Divide by 100.
- Multiply by proper voltage drop value in tables. Result is voltage drop.

**What is the maximum voltage to ground in a branch circuit?**

150 volts-

Rule 2-106 prescribes 150 volts-to-ground as the maximum voltage in dwelling units.

**What is the maximum voltage drop allowed by the NEC?**

The NEC recommends a maximum voltage drop of 5% across feeders and branch circuits, and 3% across the branch circuit alone.

## What is the maximum voltage drop permissible?

Maximum permitted levels of Voltage drop can be found in BS7671 Table 4Ab (i) 3% for lighting (6.9V) or 5% for other uses (11.5V).

### What is maximum permissible voltage drop?

The permissible voltage drop in a lighting circuit is 2% of the supply voltage plus one volt. The maximum permissible voltage drop in a power industrial circuit should not be more than 5% of the declared supply voltage. The insulation resistance of any wiring installation should not be less than 1M Ω.

#### What is the recommended maximum total voltage drop on both feeders and branch circuits to the farthest outlet?

five percent

The maximum combined voltage drop on both installed feeder conductors and branch circuit conductors to the farthest connected load or outlet must not exceed five percent. This is the steady-state voltage drop under normal load conditions.

**What is the NEC code for voltage drop?**

Voltage Drop and the NEC. The following are National Electrical Code (NEC) references with regard to maximum voltage drop: branch circuits NEC 210.19 (A) (1), feeders NEC 215.2 (A) (4), sensitive Electronic Equipment NEC 647.4 (D) and other considerations. Voltage drop calculations (formulas, phasor diagram and real-world examples)

**What is the maximum voltage drop allowed in a branch circuit?**

1. Branch Circuits – This FPN recommends that branch circuit conductors be sized to prevent a maximum voltage drop of 3%. The maximum total voltage drop for a combination of both branch circuit and feeder should not exceed 5%.

## What are the NEC requirements for single phase circuits?

This is the same requirement stated above for branch circuits. NEC 647.4 (D) covers the use of separately-derived 120 V, single-phase, three-wire systems with 60 V between each of the two hot conductors and the neutral, similar to the 120/240V service to our houses, but at half the voltage.

### What is the voltage drop on a single phase AC system?

A 3% voltage drop on a single-phase, 120 VAC system would be 0.03×120V = 3.6 V. Similarly, a 2% voltage drop on a three-phase, 480 VAC system would be 0.02×480V = 9.6V. The main concern of voltage drop calculations is to make sure the load has enough voltage to function properly.