Electric vehicle supply equipment is rated 100 amperes at 208 volts. What does the Code require for its disconnecting means?
- ANo separate disconnect is required where the branch-circuit breaker is within sight of the equipment and lockable
In sight of the equipment is not the standard here, and a breaker two floors away in a locked electrical room is neither readily accessible from the charger nor a substitute for the required disconnect.
- A disconnecting means installed in a readily accessible location and capable of being locked in the open position
- CA disconnecting means located within 3 feet of the charging equipment enclosure on the same wall
There is no 3-foot dimension in this requirement. The standard is readily accessible and lockable, which allows considerable flexibility in placement.
- DA disconnecting means is required only where the equipment exceeds 150 volts to ground
Voltage to ground is only one of the two triggers. Exceeding 60 amperes brings the requirement into play on its own.
Why B is correct
The trigger is either condition: more than 60 amperes, or more than 150 volts to ground. Meeting one is enough. Once triggered, the disconnect must be readily accessible and lockable in the open position, with the locking means remaining in place with or without the lock installed.
What this question is testing
The item tests whether the candidate can apply a two-part trigger where either condition suffices, and knows the specific attributes the disconnect must have.
On the job
Commercial charging installations are growing fast and are almost always remote from the electrical room, sometimes on a different level of a garage. Without a local lockable disconnect, servicing the unit means coordinating with building staff to find and lock out a breaker somewhere else. The disconnect also matters for emergency responders. On dwelling installations the smaller equipment usually falls below the thresholds and no separate disconnect is required.
Memory technique
Over sixty amperes or over 150 volts to ground: readily accessible and lockable.
Exam tip
When a rule says more than X or more than Y, either one alone triggers it. Do not look for both.
Where to look it up
Look in the electric vehicle power transfer system article, in the part covering equipment construction and installation, at the disconnecting means section.