A proposed 100-ampere branch circuit is intended to supply equipment whose instructions call for 125-ampere overcurrent protection. The circuit design has not been checked for that protection. What should be done before selecting a device?
- AInstall a 100-ampere breaker and ignore the equipment instructions
- Resolve the mismatch by checking conductor capacity, equipment instructions and applicable protection rules
- CInstall a 125-ampere breaker without reviewing the circuit
- DInstall a 125-ampere fuse without reviewing the circuit
Where to look it up
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.304
Why B is correct
The stated ratings reveal a mismatch that requires design review. Protection must be compatible with conductor and equipment capacity, while listed equipment instructions and any applicable specific permissions must also be checked. Choosing a breaker or fuse solely from one rating does not establish a suitable circuit.