branch circuit for forklift battery charger

[royta]

Customer has a 208V, 3ph battery charger for their forklift, which pulls 28A. Charger has a short length of 10-4 SO type cord for the branch circuit, which was installed by previous owner of charger. Under Art. 625.2, the forklift is not an Electric Vehicle, but for kicks I'll still use Art. 625.21 for my OCP. Even without Art 625.21, I still think I have to AT LEAST figure 125%.

28*125% = 35A

Art. 240(D) comes into play.

Even though charger will be installed five or so feet from panel, they still want a disconnect installed. *I think I just answered my own question* I think I'll run EMT from panel to 40A disconnect (if 35A can not be found), and then LFMC or LFNC to battery charger. Use #8 for the branch circuit. Gee, that was easy. Thanks for the help.


Roy

 

[iwire]

Under Art. 625.2, the forklift is not an Electric Vehicle, but for kicks I'll still use Art. 625.21 for my OCP.

Why?

It clearly does not apply.

Even without Art 625.21, I still think I have to AT LEAST figure 125%

Why?

The charger will not fit the definition of continuous load check Article 100.

The charger may run for 12 hours straight but its maximum load will not last 3 hours.

As the battery is charged the current will drop.

I would leave the 10/3 cord on it and supply it with a 30 amp circuit.

 

[Jim W in Tampa]

That panel is a disconnect,why add another if its that close and insite

 

[Twoskinsoneman]

Customer has a 208V, 3ph battery charger for their forklift, which pulls 28A. Charger has a short length of 10-4 SO type cord for the branch circuit, which was installed by previous owner of charger. Under Art. 625.2, the forklift is not an Electric Vehicle, but for kicks I'll still use Art. 625.21 for my OCP. Even without Art 625.21, I still think I have to AT LEAST figure 125%.

28*125% = 35A

Art. 240(D) comes into play.

Even though charger will be installed five or so feet from panel, they still want a disconnect installed. *I think I just answered my own question* I think I'll run EMT from panel to 40A disconnect (if 35A can not be found), and then LFMC or LFNC to battery charger. Use #8 for the branch circuit. Gee, that was easy. Thanks for the help.


Roy

Is the 10/4 rated for 30 amps? Most 10/4 SO I've come across was only rated for 25 amps

 

[royta]

That panel is a disconnect,why add another if its that close and insite

I suggested that, but the customer insisted. Maybe they don't want to be confused on which 3-pole breaker to quickly throw in case of an emergency. There's no point in arguing with them. If what they want meets code, then the customer is always right.

Even without Art 625.21, I still think I have to AT LEAST figure 125%

Why?

The charger will not fit the definition of continuous load check Article 100.

The charger may run for 12 hours straight but its maximum load will not last 3 hours.

As the battery is charged the current will drop.

I would leave the 10/3 cord on it and supply it with a 30 amp circuit.

I see your point. However, after a little thought, I've decided to just play it safe. I understand the current will drop as the battery is charged. By how much though? Do you know, do I know, who does know? There is no paperwork showing the curve. The only way to guarantee that it won't pull 24+ amps (30A x .8) for three hours or longer, is to control the branch circuit with a timer set for three hours or less. I'm probably being overly cautious though. However, since I will have touched it last, I will be the one owning it. Continuous load it is.

 

[LarryFine]

If what they want meets code . . .

. . . and they're willing to pay for it . . .

. . . then the customer is always right.

​

 

[infinity]

It fine to exceed what is required by code since the NEC is regarded as a minimum requirement. However IMO, as Bob has also stated, a battery charger is not a continuous load.

 

[iwire]

I see your point. However, after a little thought, I've decided to just play it safe.

Certainly nothing wrong with that, be aware that while it is common to figure 125% most times we should not exceed 150%. 422.11(E) :smile: If you go with a 40 amp breaker you are still under 150%.

Twoskinsoneman also brought up a very good point

Is the 10/4 rated for 30 amps? Most 10/4 SO I've come across was only rated for 25 amps

He is correct, used with 3 current carrying conductors 10 AWG cord is only rated 25 amps.

I understand the current will drop as the battery is charged. By how much though?

In my opinion per the definition as long as the current drops below the maximum current you have satisfied the NEC.

No mention of dropping below 80% in the definition.

:grin:

Yeah I know that is really pushing it and it is not how I would wire it. Just another way of looking at requirements using "Charlie's Rule"*

I'm probably being overly cautious though. However, since I will have touched it last, I will be the one owning it. Continuous load it is.

Not overly cautious, professional.



*"Charlie's Rule" is a registered trade mark of Charlie's Rule Incorporated.:wink: