Make swiss cheese out of the Tap rule

[bonding jumper]

Dear Forumers,
I am an Electrical Designer and frequently have to install additional loads onto existing building services after the service switch. I would like to ask for input on a contradiction between the utility (Con Edison) and the NEC 25' Tap rule. The 25' tap rule states that your tap must terminate your tap conductors into an overcurrent protection device. I see frequently a service switch feeding a copper bus in a trough. Then tap conductors taken from that copper bus to feed a meter that is greater than 10' of conductor from the bus, then from the meter to the overcurrent protection device. Is there some exception that I am missing that permits this? I can say conservitively that this happens in 30% of all building in nyc. Thanks.

Edit: I also find it disturbing that if I wish to add a single disconnect from that bus after the service switch, I am required to comply with the NEC tap rules. But however, if I decided to tap the service bus, before the service switch, I have absolutely no tap rule to abide by and can run the conductors any desired legnth as long as my new disconnect switch is "service rated" and grouped with the other service switches. Thanks in advance.

[ July 16, 2004, 12:19 PM: Message edited by: bonding jumper ]

 

[steve66]

Re: Make swiss cheese out of the Tap rule

The utility company does not have to follow the NEC rules. I think they usually follow another set of rules (NESC?), but I not sure if that is leagally required, or just standard practice.

There is also an outside tap rule in the NEC for unlimited lengths.

Steve

 

[don_resqcapt19]

Re: Make swiss cheese out of the Tap rule

bonding jumper,

But however, if I decided to tap the service bus, before the service switch, I have absolutely no tap rule to abide by and can run the conductors any desired legnth as long as my new disconnect switch is "service rated" and grouped with the other service switches.

Only where the service tap conductors are outside and the service switch is "nearest the point of entrance".
Don

 

[bonding jumper]

Re: Make swiss cheese out of the Tap rule

Originally posted by steve66:
The utility company does not have to follow the NEC rules. I think they usually follow another set of rules (NESC?), but I not sure if that is leagally required, or just standard practice.
Steve

Correct, I agree. To my understanding, the utility rules stop at the line side of the service disconnect switch. So I want to tap from the load side bus of the service switch use the 25 foot tap rule and terminate into a meter, then a fused disconnect switch. This is illegal by code cuz I need to terminate my tap directly into a ocpd, not a meter, and cuz its after the service switch which should be NEC territory, the utility has the right to force me to break the rules?

 

[steve66]

Re: Make swiss cheese out of the Tap rule

To my understanding, the utility rules stop at the line side of the service disconnect switch.

I don't think that is necessarly true. The serving utility determines where the "service point" is. Their rules apply on their side of the service point, the NEC applies on your side. They have no control what you do on your side (which is why they usually call the load side of the meter "your side").

So it may be that the service point is the load side of the meter (even if you have to provide conduit or enclosures on their side).

Steve

 

[necbuff]

Re: Make swiss cheese out of the Tap rule

I believe if the tap is under 10' it does not have to terminate in a OCD. But the equipment (device) at termination can not be rated less than the feeder conductors, along with other non topic related requirements. Over 10' would require the feeder taps to terminate in a single OCD or set of fuses.

 

[goodcode]

Re: Make swiss cheese out of the Tap rule

Want to add confusion to a code discussion or just prolong it enough to polish off a case of beer, through in a tap.
Dealing with "tap Conductors" within the NEC is not all that difficult. Taps are conductors not protected at their rated ampacities. Service conductors are never taps, they are service conductors, subject to the rules of Article 230 until they terminate in a disconnecting means and overcurrent protection.
There is a serious distinction between service conductors and utility owned conductors. The line in the sand is the "service point" as defined by Article 100. The utility does not determine the "service point," it is determined by the point at which the utility owned conductors meet "premises wiring."
The statement by Don is absolutely correct. Where utility engineers desire to, they may take great liberties outside of a structure, as well as the scope of the NEC to more easily facilitate their installation.
The tap rules are not written only for the load side of service equipment. They apply through out all electrical installations, large and small. A review of the ROP & ROC and the TCD/TCRs of the past document the reasons for these rules.
This forum has no shortage of qualified moderators to help forum visitors with problems in the NEC. The issue at hand in this posting should/could manifest itself in a proposed code change. The NEC process works best when interested persons including "utility engineers" submit proposed changes to the NEC.

 

[a.wayne3@verizon.net]

Re: Make swiss cheese out of the Tap rule

Mind if I share that case with you The POCO has their own agenda to go by.I don`t concern myself with what they are allowed to do or not to do.Last year a crew digging up a pool hooked 350 mcm THHW that was burried to feed transormers,I contacted the AHJ,out of their jurisdiction.Tell that to the guy that had his bucket melted.

 

[charlie]

Re: Make swiss cheese out of the Tap rule

Wayne, it would be interesting to know a bit more about your "case". For instance, was locates called for? Was an easement involved? Do you know all the facts? How was the case settled? You have raised an interesting subject but we don't know what happened.

Goodcode, you are absolutely correct and some proposals have come from some of the members of this forum. The thing that everyone here needs to remember is that the Code is not written by the Code Making Panels but by the users of the Code who submit proposals. The bottom line is that no proposals mean no changes. If something is sticking in your craw, make a proposal to the 2008 Code Making Process. Who knows, I might even get one of my own passed this time.