Does 10' tap rule length include equipment?

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ritelec

Senior Member
Location
Jersey
Hello..

There's a feeder supplying several meters..

Lets say theres a 400 amp service switch then goes into a trough and then from that trough conductors are tapped to go through a meter then to the main disconnect for each tap.

What is considered in the 10' length? Everything from the tap to the ocp? Would it be considered from the point of the Tap on the feeder "AND" through the meter, and out of the meter to the first disconnect (ocp)?
I'm thinking so, but checking? And I'm also making sure that the Tap "conductors" have to be rated no less than 1/10 the feeder ocp. The meter doesn't have conductors so I'm thinking it would have to be rated for the ampacity of the tap conductors? And for my head in that 240.21 section where it says that equipment can be between the tap and ocp.


Also, I'm looking through changes to the 2014 and see that tapping a tap is a violation. Looking in the code book I can't locate that.. please point me.

I'm trying to get my "facts" together when talking to a landlord this week.

The actual 400 amp switch feeds a small trough with 500's, from there it's tapped with smaller conductors to another trough that taps to smaller conductors feeding 9 meters to some panels or 2 pole main breakers.
Also from the small 400 amp trough it's tapped again with smaller conductors to feed a trough that has taps to smaller conductors feeding 3 more meters and main breakers (or fuses).

These taps from the 500's to the last meter/disconnects are +- 20' away.

The whole service needs to be redone, it's very old and if you look up you see all the existing floor joists and beams that had been in a major fire years ago. Opening things up they are feeding neutral loads from taps with no neutrals (going to through).. 3 phase motor loads with 2 two wire romex…….. a real mess.. and old.

I keep mentioning to the landlord, I really don't want the liability, but I will fix the whole thing..…….. he keeps saying he wants to fix it all then directs me back to "just" replacing the burnt out older meter..???

So besides the blatant wiring that is wrong (ground as neutral, open splices, 2-2wire as 3 wire….tandems, tandems and more tandems, I'm also trying to get together in my had the tap rule that is not right (and for my personal education.

Thank you..
 

jumper

Senior Member
As for tapping a tap and why it is not permitted:

240.21 Location in Circuit. Overcurrent protection shall be
provided in each ungrounded circuit conductor and shall be
located at the point where the conductors receive their supply
except as specified in 240.21(A) through (H). Conductors supplied
under the provisions of 240.21(A) through (H) shall not
supply another conductor except through an overcurrent protective
device meeting the requirements of 240.4.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Conductors on the line side of the service disconnect(s) are just service conductors. They are not covered by the tap rules in Article 240.
 

ritelec

Senior Member
Location
Jersey
I am inclined to agree but the OP is confusing to me enough that I am not sure that is what he is describing.

Sorry for the confusion.

The service in this case is 400a 3 phase four wire underground city sidewalk to a 3 phase fused disconnect.

From that disconnect it goes out to the first trough with 500's then twice out from that trough with smaller conductors to two troughs with those troughs getting multiple taps to meters and tenant service mains

From what I'm understanding. ALL the taps to each meter would have to come off the 500's to each meter and not off the smaller tap wire from the 500.

Also. The smaller taps off the 500. Each of those tap lengths before the next tap to the meters are about 20 '

Would the main 400 amp and everything load side of that disconnect andine side of the meters and oc for each tenant be considered service and not apply to tap rules ???

Would like to ask also. A 400 amp fuse blew from an older three phase meter (the type with wiring taken out of a box below the meter and the meter is secured to a piece of steal sheat. I'll post a pic. On my phone now ) but

The old meter supplying a 150a panel somehow burnt and blew a 400 a fuse. Ok understood.

But as it was that way for several hours as I and the utility worker's were standing there not touching our doing anything. The pizza shop who's panel it was was done for the day but it started burning and smoking against the mounting board. Just find it strange how it waited to do it till the three of us where standing in front of it. The utility worker did not hesitate and just opened the 400 amp switch.

Wondering why the fuse blew when the meter had a melt down. But when I and the utility workers where there and it stated burning and smoking like a welder why another fuse didn't blow.


So do not the tap rules apply to line of meters which are after a main disconnect supplying those meters and house panels.?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Tap conductors must end at an OCPD. IMHO that prohibits running a tap through a meter before it reaches the OCPD.
On the other hand the length of feeder taps may not be limited as long as they do not run more than the limited distance inside a building.
 

ritelec

Senior Member
Location
Jersey
Tap conductors must end at an OCPD. IMHO that prohibits running a tap through a meter before it reaches the OCPD.
On the other hand the length of feeder taps may not be limited as long as they do not run more than the limited distance inside a building.

wondering… something simple… ? a house, 200 amp down seu to an exterior trough, two nipples out to two 100 amp meters, than from those meters to a basement to two main lug panels.

Are you saying it would have to be 200 amp wire through the meters to the 100amp panels??
 

ritelec

Senior Member
Location
Jersey
okay…… 400 amp disconnect.. top right looks to be a 200 amp disconnect coming from the street that fed original trough.. it is fed from smaller through at left of 400 amp disconnect.. the wires from the street are cut and taped and the wires are bugged from the 400 amp to refeed the trough in that 200 amp disconnect enclosure
 
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ritelec

Senior Member
Location
Jersey
burnt meter..bottom tap feed, also feeds that smaller meter and fed pac panel and another meter to the right from that 1 1/4 newer pipe
 
That was a pretty common setup back in the day. I redid one very similar to yours a few years back - the backboard was even the same, black boards! The point golddigger brings up about the tap terminating on a meter is an interesting twist I never considered. IT could be argued that considering the definitions of feeder, the meter socket is just a conductor, and then (responding to your OP) it would count as conductor length toward the tap length allowance.
 

ritelec

Senior Member
Location
Jersey
In ref to bonding.
In theory, the drawings seem correct… I wonder if the supply houses or utility have meters (neutral) that look different (bonded,floating)… if they are all bonded, I "guess" they just go in?

And as in the pictures, it looks like no grounding lock nuts or bushings are required if a main is installed before their metering..

(these pics are from utility company specs in my area, the utility company is different at this job location, but I would think specs should basically be the same)
 

kwired

Electron manager
Location
NE Nebraska
even if the meters are allowed in the tap conductors - many of the ones pictured still do not end at a single overcurrent device from what I can tell. Each of those panels would need to have a main breaker installed.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
even if the meters are allowed in the tap conductors - many of the ones pictured still do not end at a single overcurrent device from what I can tell. Each of those panels would need to have a main breaker installed.

yep.

I also wonder if the main disconnect is fused or not. if it is fused wouldn't that put the service point there?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
In ref to bonding.
In theory, the drawings seem correct… I wonder if the supply houses or utility have meters (neutral) that look different (bonded,floating)… if they are all bonded, I "guess" they just go in?

And as in the pictures, it looks like no grounding lock nuts or bushings are required if a main is installed before their metering..

(these pics are from utility company specs in my area, the utility company is different at this job location, but I would think specs should basically be the same)

can you actually make the connection to the water pipe street side? I thought it had to be inside.
 
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