New Rule May Call for Main Ahead of Meter!

[jtedesco1]

[Greg Fretwell]

The new rule in 230.82(3) in 2005 says they "shall be permitted" to be on the line side of the disconnect, not that they "shall" be there.
The real implication is specifying that this is a meter disconnect, to establish this is NOT the service disconnect so we are not conflicted about where the main bonding jumper goes. The basic permission was in 230.82(2) prior to this.

[jtedesco1]

Originally Posted by Greg Fretwell

The new rule in 230.82(3) in 2005 says they "shall be permitted" to be on the line side of the disconnect, not that they "shall" be there.
The real implication is specifying that this is a meter disconnect, to establish this is NOT the service disconnect so we are not conflicted about where the main bonding jumper goes. The basic permission was in 230.82(2) prior to this.

Greg: In the title use of the word "May" was intended to be understood as it was once used, and now the "shall be permitted" text is used, so the rule is not mandatory. One of the reasons this was added is summerized here:

Arc created while breaking load current on a 480Y/277-volt system (277 volts to ground) could transfer to the grounded equipment enclosure and create a high-energy arcing ground fault and arc flash that could develop into a 3-phase short circuit.




This hazardous arcing could burn down the meter socket, and injure the person performing the work.

[Greg Fretwell]

If you are really concerned, why not just use a 3R service disconnect? That is becoming the standard on piling houses around here anyway. Most big commercial has outside disconnects. Once you have opened the load side of the meter there shouldn't be any arc issues but the jaws are still hot.
The POCO doesn't hesitate to open the pole fuse when they need to.