Posted Jul 26, 2023
SHELTON, CT - Recently, Lex Products learned of a practice commonly used in the assembly and disassembly of electrical connections between motor controllers and hoist motors. We have been made aware that hoist motor connections are often mated and unmated while the extension is electrically energized. In other words, the circuit is closed. These cables are not to be connected or disconnected while the circuit is energized. This practice can lead to serious risk of electrical shock.
According to NEC Section 430.109 – Type, the disconnecting means employed must be a type that falls under the categories specified in Subdivision 430.109(A), unless specifically permitted in Subdivisions 430.109(B) through (G) under the given conditions. The NEC emphasizes that a circuit’s conductors should only be disconnected using one of the following acceptable means:
1. Motor Circuit Switch
2. Molded Case Circuit Breaker
3. Molded Case Switch
4. Instantaneous Trip Circuit Breaker
5. Self-Protected Combination Controller
6. Manual Motor Controller
7. System Isolation Equipment
It is important to note that before making or breaking a connection in a circuit, it must be opened (deenergized) using one of the above-mentioned means to comply with the NEC regulations.
There is an exception in NEC Subdivision 430.109(F) – Cord-and-Plug-Connected Motors. In this context, a disconnecting means for such motors must be in the form of a horsepower-rated attachment plug and receptacle, flanged surface inlet and cord connector, or attachment plug and cord connector with ratings no less than those of the motor.
The types of wiring devices used in the industry for hoist motor power and control (including 14-pin ¼-turn, 7-pin ¼ turn, and 7-pin ‘Socapex’) are not horsepower rated, therefore, utilizing them as a disconnecting means is expressly prohibited by the National Electrical Code (NEC Subdivision 430.109 (F)).
Effected Lex Products part numbers:
Our goal is to ensure that you are aware of the standards set forth by the NEC pertaining to these devices so that they can be used in the safest possible way, and in a way that optimizes the longevity of the product.