Circuit breakers for the drives in a control panel.

T

touge

Member
Location
Taiwan
Occupation
engineer
Hi experts,

I am importing some machines from China to the US.
Based on my understanding, UL certification is not mandatory.

However, for safety concerns and future use, I still hope they could meet at least NFPA70/79 or UL508A.
I am not very familiar with electrical code requirements in US, so I am seeking some help.

I am confused about the requirements for the circuit breaker inside of the control panel.
In this panel, we have 10 servo drives and 2 VFDs, with power rating from 0.75 kW to 7.5 kW, and other PLC devices.

The vendor is using a Schneider OSMC65H MCB for each drive.
OSMC65H is a UL1077 breaker that is only supplied in China.

As per my understanding, it does not meet NFPA requirements.
I must change these MCB to a UL489 MCB.

However, due to lead time and price concerns,
I am looking for alternative options for these breakers.

1.GV2ME is a UL-listed manual motor starter (neither E/F type) recommended for group motor applications.
GV2P is a UL 60947-4-1 type E, and this model is also recommended by Schneider for their own servo drives.
Could I use GV2ME to meet the code for the infeed of drives, or must I use GV2P?

2.We have a panel cooling unit for this panel.
Can I use a manual motor starter as the circuit protection, or do I need to use a UL489 breaker?

3.For the external pump, can I use a manual motor starter as the circuit protection, or do I need to use a UL489 breaker?

4.Are there any other devices for which I need to use a UL489 breaker? There are no other branches in this panel.

Thank you!
 
What makes you think you cannot use a UL 1077 breaker in this application? A lot depends on the actual circuit but there are cases where a 1077 breaker would be acceptable.

You can't use a manual motor starter on anything other than a motor circuit.

I don't know what you're trying to accomplish so it's hard to give you any real advice. It seems likely that if the overcurrent protection devices do not meet US code that there are probably other things that might be an issue.
 
In WA your project would have to be UL or NRTL listed for the control panel and drives, if a permit was pulled.
 
Hi all,
Sorry for late reply and thank you for your replies.
I will choose GV2P due to the limitation of SCCR rating.
 
I can understand the confusion around circuit breaker requirements, especially with different standards between China and the US.
 
GraceShah said:
I can understand the confusion around circuit breaker requirements, especially with different standards between China and the US.
Click to expand...
Considering your situation, MCBs like the UL489-compliant ones you mentioned are generally the safer bet for meeting US electrical codes. While alternatives like GV2ME might work for some applications, they might not tick all the boxes for your servo drives and VFDs.As for your cooling unit and external pump, sticking to UL489 breakers would likely be the safer route, ensuring proper protection for your equipment.
 
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