FLA and FLC

FLA – Full Load Ampere

FLC – Full Load Current

FLA = FLC

Literally, both of the terms can be used for full load current (or ampere) for any electricity driven equipment but they are mostly used to indicate the maximum current (in ampere) that a motor can draw when it is fully loaded.

Though the motor name plate current also indicates the same thing but NEC makes a difference between FLA and name plate current. In NEC, the term FLA is used for indicating the motor full load current defined in article 430 but the name plate current is the motor full load current indicated by the vendor and their value may differ. In fact, FLA is the full load current of a particular set of motors (such as same HP, same voltage) in general but the name plate current is the full load current of a specific motor.

- MS

1- For sizing breaker and wire for motors FLC (Full Load Current) is used.

2- FLA (Full Load Ampere) , is always shown in Motor's nameplate, is used to size overload protection for motors.

If you are using NEC-2008 please refer to to table 430 part XIV there is FLC and you need to size circuit ampacity and also read Artical 430.51 and 430.31

for the most part they both are same but for motors the FLA of a motor is less than the FLC in the tables.

Please also see the image FLA is not equal to FLC

NEC itself doesn't differentiate between FLA and FLC. For motor nameplate current, it some times says "nameplate full-load ampere" and sometimes "nameplate full-load current". See these two sections for example:

430.32 (A) (1) - "motor nameplate full-load current"

610.14 (E) (1) - "motor nameplate full-load ampere"

The difference is when the word "nameplate" is used.

So, these are the interpretations per NEC:

Full Load Current = Full Load Ampere

Nameplate Full Load Current = Nameplate Full Load Ampere

Nameplate Full Load Current ≠ Full Load Current

Nameplate Full Load Ampere ≠ Full Load Ampere

However, somebody else may interpret it differently.

- MS

According to

"Electrical Inspection Manual with Checklists, 2008 Edition By Noel Williams, Jeffrey S. Sargent" , page# 203

it states " Artical 430 provides tables of full laod current (FLC) values for motors of various characteristics. The current values from the tables must be used in calculating values for conductor ampacities, short-circuit and ground fault devices, disconnect ratings, and so on.

The full load ampere( FLA ) rating provided on the nameplate of a motor is used only for sizing overload protective devices for the motor.


FLA value from a nameplate is greater than the corresponding FLC value from the table.

For torque motors, the nameplate is used because the motor normally operates in a locked-rotor condition. Calculating for alternating current adjustable voltage motors and adjustable speed drive systems are based on the nameplate of the controller or power conversion equipment".

Just to add some historical clarification:

NEC section 430.7 (A) (2) says what current should be marked in the motor nameplate. Before NEC 2005 (till NEC 2002), it was worded as "Rated volts and full-load ampere". This made some people feeling that the motor nameplate current is called FLA. But NEC didn't have intention to differentiate between FLA and FLC. To stop people thinking these two terms differently, NEC 2005 changed the section 430.7 (A) (2) to ""Rated volts and full-load current" (along with other related changes) to clearly indicate that whatever found in motor nameplate is not specifically FLA, it is basically motor nameplate FLC (or nameplate FLA). However, some people still would like to interpret FLC to apply specifically to motor nameplate current, and it is an old and wrong (with full respect to them) way of the interpretation of NEC.

Hope it is clear now.

- MS

Ok one more thing.This reference is not an old one. It is 2008 Edition, I have it."Electrical Inspection Manual with Checklists, 2008 Edition By Noel Williams, Jeffrey S. Sargent" , page# 203"

This reference 2008 Edition is by William, and Jeffrey S.Sargent. These both two guys are the editor of 2008 NEC edition.

I think it is not an old statement.You may have only NEC hand-book 2008 but NEC hand-book 2008 is not in detail discussion. Please see this "Electrical Inspection Manual" it explains NEC's articles in detail with additional information.

And these examples and images by " Mike Holt, NEC Consultant ". Please read the bold text.

Example No. 2: Again, suppose you're using a dual-element fuse for the overload protection. What size fuse do you need for a 50-hp, 460V, 3-phase motor that has a temperature rise of 39°C and motor nameplate current rating of 60A (FLA)?

(a) 40A
(c) 60A
(b) 50A
(d) 70A

The overload protection is sized per the motor nameplate current rating, not the motor full load current (FLC) rating. Thus, 60A×1.25=75A. Overload protection shall not exceed 75A, so you need to use a 70A dual-element fuse [240.6(A) and 430.32(A)(1)].

Example NO.2

Sizing branch-circuit conductors. Branch-circuit conductors that serve a single motor must have an ampacity of not less than 125% of the motor's FLC as listed in Tables 430.147 through 430.150 [430.6(A)]. You must select the conductor size from Table 310.16 according to the terminal temperature rating (60°C or 75°C) of the equipment [110.14(C)]. Let's reinforce this concept by working through a sample calculation. Refer to Fig. 4.

It is about NEC and the explanation of NEC by some experts. I never disagreed to what you said. What I want to say is the NEC's stand regarding FLA and FLC. I also wrote the brief history in this context. I didn't say the book you referred is an old one but as I said earlier "some people still would like to interpret FLC to apply specifically to motor nameplate current". I am fully aware of the giant guys (Mike Holt, James Stallcup etc.) and often use their explanation, when needed. Their works are pretty well and definitely helps other people to understand NEC but there are many other people who understand NEC without their work. Explanation of NEC by some experts doesn't not supersede the NEC itself. All quote I mentioned in this thread are from NEC but your's are somebody else's work on NEC.

Anyway, I think that's it from me for this simple thread.

- MS

ok thanks for nice discussion.

ok thanks for nice discussion.

Just can't help myself - deer fallows - fallow deer - oh dear.

Dont' worry, you have also received some useful answers.