Regarding Mark's(marktlm123) comments about PoCo employees recieving shocks when removing meters to isolate installations.
Is this a recognised practice(removing the meter)?.
I would have thought that there would be a fuse or some other device, on the Line- side of the meter, to do this(isolate the installation) in a safer way?.


[This message has been edited by Trumpy (edited 05-02-2003).]

There's always a main fuse ahead of the meter in the U.K., but then our meters aren't the plug-in type.

Trumpy and Paul — In the US, the norm is called "hot-sequence metering" and has some limitations.

Found at themeterguy web site...




[This message has been edited by Bjarney (edited 05-25-2003).]

Several years ago the Utility (POCO) on Long Island changed the Meter Pan requirements to include a Manual Bypass Lever in all new installations including Residential. This allows the meter to be pulled or inserted after the switch is closed without any arcing.

Bill

Bjarney,
Thanks for the pic, mate.
You were saying that this system has it's limitations, what are these?.

Some OH drops are less intimidating , and easier to deal with than older cruted up meters.

Trumpy, I think the limitations Bjarney is speaking of are those that show in the picture.

Bad things can happen pulling and replacing meters Hot.

As sparky said some times better to cut off the overhead but at some point you will be reconnecting Hot which brings its own problems.

We are finding more utilities going with "cold" sequence(Main ahead of CTs) metering for services above 400 amps.

Oh, if you have not seen the back side of an undamged meter I guess the picture is not much help. The meter shown has a lot of metal missing.

Hopefully the missing metal was not blasted on to any persons.

[This message has been edited by iwire (edited 05-02-2003).]

iwire, that's a good comment. The left blades in the meter photo represent the load-side three phases, plus the neutral tap on one of the middle stabs—at the lower side of the meter socket when operating. The three melted "nubs" at the right side of the picture were once ‘full-sized’ more like the 8-o’clock blade, and normally connected to the ungrounded line-side phases.

Not having the right PPE—it may have been hard to leave such an incident without copper-plated knuckles and eyebrows {and less-than-tidy underwear.}




[This message has been edited by Bjarney (edited 05-02-2003).]

How many here will fess up to doing a residential panel change,entrance cable and all,by simply removing the meter, leaving the line side of the meter base hot?

I don't do it any more,but I'm betting others have done it also.

With these meters it's commom for about 5 houses to be on one bucket(tansformer), so if your pulling a meter thats old or has problems you have about 1000 amps plus at 240 behind that and thatb wil hurt you. I think from know on i'll the power company remove the meter, it's there there equipment and they usaly lock it out so let them deal with it.

Pulling meters is something I learned while a FF/EMT in KY for several years. I pulled hundreds of meters when responding to house fires to kill the power and had one :blow up" on me. I turned out to be the bigger of the emergency than the house fire. That was the last one I pulled and NEVER will I screw around with electricity again. By the way, I was getting my BS in Safety Engineering while I was a FF/EMT and only wish i had learned of LOTO sooner!!!!

Bryan www.SAFTENG.net

Hi there Bryan!!,
I just wondered if this was a practice that would be frowned upon by the Safety Authorities?.
Sounds pretty dangerous to me!.
I've pulled hundreds of Pillar box and Pole fuses for the Fire Service, the last thing you need when spraying water around in a house, is some live wires or a switch-board.

The maximum available fault current at the secondary terminals of a 25 kva transformer is about 7000 Amps. For a 37 1/2 kva the current is over 10,000 amps. Both these are the most common sizes used in residential areas. Besides the burn hazard don't forget the hazard due to broken glass. Always wear "grabit" gloves when handling whr meters.

Ichabod

I do.

Sometimes i'll cut the OH (if there is an OH) , sometimes i pull the meter.

That's about the only two options i have...

There are gizmos that limit the hazard of meter pulling and insertion, but they are primarily marketed to utility meter departments.
http://www.meterpuller.com/homemeterpuller.aspx

interesting device Bjarney.

have you used one?

No, I have not. The metering I have installed or serviced was in an institutional/research setting, {not in the conventional utility sense} and was universally instrument-rated. [That is, current and potential transformers served the meter nominally rated 120 volts and 5 amperes regardless of the metered-circuit voltage. In this case, the same rating of meter is used for everything from 208V to 115kV {and up to 765kV for bulk-power nodes.}

Except for transmission circuits, there were always current-limiting fuses installed upstream of the PTs, and an isolation/test switch in the meter enclosure or switchboard compartment was opened/bypassed before removing or installing a socketed meter, or the meter was “switchboard” cased, making it unremovable in the same way a socketed meter could be.