Thiết bị & Hệ thốngCâu 258 / 521
The 'Maximum Overcurrent Protective Device' (MOCP or 'Max Fuse/HACR Breaker') rating on an HVAC nameplate specifies what?
a.The smallest breaker that will start the unit
b.The largest fuse or circuit breaker permitted to protect the branch circuit
c.The required conductor size
d.The disconnect switch rating only
Giải thích
The MOCP is the maximum size of fuse or HACR-rated breaker allowed for the unit's branch circuit; you may install this size or smaller, but not larger. MCA sets the conductor ampacity; the two values are used together per 440.4(B).
Trích dẫn luật: 2023 NEC §440.4Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- A motor control circuit tapped from the load side of the motor branch-circuit protection is generally protected against overcurrent according to which NEC provision?
- A single hermetic refrigerant motor-compressor has a rated-load current of 24 A. Per NEC 440.32, what minimum branch-circuit conductor ampacity is required?
- On an air-conditioning unit nameplate, what does the 'Minimum Circuit Ampacity (MCA)' value tell the installer?
- An A/C condensing unit has a compressor rated-load current of 18 A and a fan motor of 2 A. Using the 125%-of-largest-motor-plus-others method, what is the minimum circuit ampacity (MCA)?
- For a hermetic motor-compressor with a rated-load current of 18 A, what is the maximum branch-circuit short-circuit/ground-fault protective device, based on the 175% value of NEC 440.22(A)?
- If a motor-compressor (rated-load 18 A) will not start on the 175% device, NEC 440.22(A) permits increasing the protection to a maximum of what value?
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