Mike Dolt Enterprises
Mike Dolt Enterprises
User: dcheser, Location: New York
Asked on: Wednesday, April 27, 2011 at 4:54 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:41 am EDT
Question: I have run into an existing system that is to be moved to a new location. The system is a monorail system with electrically operated hoists. There are multiple hoists that can move around on the monorail and when they reach their destination the hoist plugs into a power point that is located overhead to power the hoist. There are 24 power points that all share a common feed, The power points are all jumped together (daisy chained) from one power point to the next. The individual power points have know overcurrent protection or disconnecting means other than that of the main feed breaker.I know 230.71 references a maximum number of disconnects for service entrance conductors would this apply in this instance or is there another reference you could refer me too.
Electrical Code Reference
The referenced section, 230.71, applies to branch circuits and not to the scenario you have described. However, the following code sections are relevant
ARTICLE 430 - MOTORS, MOTOR CIRCUITS, AND CONTROLLERS
430.110 Overload Protection.> Motor circuits shall be protected against overload by only one of the following means:> 1. A separate fuse or an inverse time circuit breaker.> 2. A thermal protector integral with the motor.> 3. A motor short-circuit protector.430.150 Motors on Overhead Rail Systems.> (B) Disconnecting Means.> Each motor on an overhead rail system shall have a disconnecting means installed within sight of the motor and readily accessible.
ARTICLE 440 - AIR-CONDITIONING AND REFRIGERATING EQUIPMENT440.12 Motors on Branch Circuits for Two or More Motor-Compressors.> (B) Disconnecting Means.> Where single-phase motors are connected to a single-phase branch circuit having two or more motors, each motor shall have an individual disconnecting means within sight from the motor location.
CONCLUSION
Based on the code sections cited above, it appears that each hoist should have its own disconnecting means within sight of the hoist. This disconnecting means can be a circuit breaker or a switch-fuse combination. Daisy-chaining multiple power points without individual overcurrent protection or disconnecting means is not permitted. Flag for review