The Utility Accessible Net Metering Disconnect

[stevenal]

Apparently it's a deal breaker for residential PV systems, so the industry has successfully lobbied against it. An NREL report can be found at

http://www.nrel.gov/docs/fy08osti/42675.pdf.

I'm truly amazed that the report can discuss utility worker safety practice with no mention of OSHA.

The various other disconnects are listed with no mention of the fact that of the eight, only the meter base is accessible (well it's supposed to be anyway) to the utility 24/7.

One item we being asked to trust is the invisible, inaccessible, relay inside the inverter. OSHA has already published an interpretation regarding the use of a similar electronic device (a PLC) for safety related functions.

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=25947.

It can only qualify as an alternate means after an employer (utility in this case) has jumped through too many impossible hoops.

So we are back to the meter. I'm not aware that meters have ever been recognized as a suitable load break device, although they are commonly used that way. Meters are also known to pull the guts out of meter bases when extracted.

So finally to my question. How are utilities that have waived the disconnect rule, or those that are regulated by commissions that have waived the rule, obtaining the isolation required by OSHA? For example; it is determined that the terminations on the secondary bushings of the distribution transformer must be redone de-energized. The utility side is disconnected by pulling a primary fuse or elbow. System maps indicate one of the affected customers has a PV system, though. No one is home, and the sun is shining. What is your next step?

Thanks.

 

[davidbeach]

Per the Oregon net metering rules (applies to us, not to you), we have to accept the meter as the disconnecting device for up to 12.5kW of inverter on a 120/240V service. Above that we can, and do, require an accessible lockable disconnect. We can disconnect, include pulling the meter, as needed.

The customer-generator’s electric service may be disconnected by the public utility entirely if the net metering facility must be physically disconnected for any reason.

If the customer's meter base doesn't respond well to the meter being pulled, isn't that the customer's problem? But the important thing is that we don't need permission to disconnect the customer's generation.

 

[stevenal]

David
If still energized when pulled and the base does not respond well, the puller bears the safety risk.

Customer may (be)disagree(able) when he learns late on Fri. afternoon that his base that was functioning just fine Fri morning now needs to be replaced.

Do you have the table that goes with 860-039-0015(1)(a)? If so, could you post it? Thanks.

 

[davidbeach]

860-039-0015
Installation, Operation, Maintenance, and Testing of Net Metering Facilities
(1) Except for customer-generators established as net metering customers prior to the effective date of this rule, a customer-generator of a public utility must install, operate and maintain a net metering facility in compliance with the IEEE standards.
(2) Except for customer-generators established as net metering customers prior to the effective date of this rule, a customer-generator of a public utility must install and maintain a manual disconnect switch that will disconnect the net metering facility from the public utility’s system. The disconnect switch must be a lockable, load-break switch that plainly indicates whether it is in the open or closed position. The disconnect switch must be readily accessible to the public utility at all times and located within 10 feet of the public utility’s meter.
(a) For customer services of 600 volts or less, a public utility may not require a disconnect switch for a net metering facility that is inverter-based with a maximum rating as shown below.
Service Type—Maximum Net Metering Facility Size (kW)
240 Volts, Single-phase, 3 Wire—7.2
120/208 Volts, 3-Phase, 4 Wire—10.5
120/240 Volts, 3-Phase 4 Wire—12.5
277/480, 3-Phase, 4 Wire—25.0
For other service types, the net metering facility must not impact the customer generator’s service conductors by more than 30 amperes.
(b) The disconnect switch may be located more than 10 feet from the public utility meter if permanent instructions are posted at the meter indicating the precise location of the disconnect switch. The public utility must approve the location of the disconnect switch prior to the installation of the net metering facility.
(3) The customer-generator’s electric service may be disconnected by the public utility entirely if the net metering facility must be physically disconnected for any reason.

The customer is always welcome to provide the disconnect we can't require. We will require it for every installation we are permitted to require it.

 

[stevenal]

Thanks David,

Don't know why they couldn't have included a four line two column table in the on-line version.

 

[davidbeach]

Steve, I don't know which "on-line" version you might have been looking at, but try

http://www.oregon.gov/PUC/admin_rules/div039.pdf

from which I copied the above.

 

[stevenal]

http://arcweb.sos.state.or.us/rules/OARS_800/OAR_860/860_039.html

was the one I found.