Blender in Commerical Application

new_ee · Jul 22, 2005

I have a single phase 110/120V blender rated at 18A. I dont think it should be considered continuous load. the manufacturer recommends the blender be protected with a 20 amp circuit breaker and be on its own circuit. should the blender be considered a motor and the breaker be rated at 2.5X the load? it will be on its own nema 5-20R outlet. im not sure if 422 appliances or 430 motor loads applies here. 422.11(G) is what is confusing me.

charlie · Jul 22, 2005

Re: Blender in Commerical Application

the manufacturer recommends the blender be protected with a 20 amp circuit breaker and be on its own circuit.

110.3(B) Installation and Use Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

It sounds to me like you need to comply with 110.3(B). I am assuming that you have gotten the information from the manufacturer's instructions.

growler · Jul 22, 2005

Re: Blender in Commerical Application

110.3(B) Installation and Use. Listed or labeled equipment "shall be" installed and used in accordance with any instructions included in listing or labeling. This is the one I go to for equipment installation. If it doesn't work, I haven't voided any warranty.

charlie b · Jul 22, 2005

Re: Blender in Commerical Application

Good question! You are thinking this through better than I could have, when I was a "new EE."

My answer is that a 20 amp branch circuit is appropriate for this load. Here's my reasoning:

Start with 422.11. It says to protect motors against overloads using sub-paragraphs A to G and using 422.10. We'll come back to 422.10 later.

422.11(G) tells you to go to 430.

Within 430, the discussion of overload protection begins in Part III, article 430.31. That is just a general discussion.

430.32 does not apply, as your motor is not continuous.

430.33 says that for intermittent duty motors you can use the circuit breaker, so long as the overcurrent setting is within Table 430.52.

You are talking about a 20 amp breaker and an 18 amp load. That is overcurrent protection at 111%. This is well within the limits of Table 430.52.

Back to 422.10. Since this is an individual load, and since it is not continuous, you do not need to use the 125% factor.

Therefore, a 20 amp branch circuit will work.

QED

new_ee · Jul 22, 2005

Re: Blender in Commerical Application

Originally posted by charlie b:
Good question! You are thinking this through better than I could have, when I was a "new EE."

My answer is that a 20 amp branch circuit is appropriate for this load. Here's my reasoning:


Start with 422.11. It says to protect motors against overloads using sub-paragraphs A to G and using 422.10. We'll come back to 422.10 later.



422.11(G) tells you to go to 430.



Within 430, the discussion of overload protection begins in Part III, article 430.31. That is just a general discussion.



430.32 does not apply, as your motor is not continuous.



430.33 says that for intermittent duty motors you can use the circuit breaker, so long as the overcurrent setting is within Table 430.52.



You are talking about a 20 amp breaker and an 18 amp load. That is overcurrent protection at 111%. This is well within the limits of Table 430.52.



Back to 422.10. Since this is an individual load, and since it is not continuous, you do not need to use the 125% factor.



Therefore, a 20 amp branch circuit will work.

QED

Wow. Thanks for taking the time to post that. That is the exact process I went through. Being new, I guess I'm just a little unsure of myself.

Blender in Commerical Application

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