No overcurrent for SE thru attic

[mark petty]

1983 block home on slab with overhead service: Typical meter can on the outside with no disconnect and SE cable running approximately 25 feet thru attic (not in conduit) and then down to main panel at opposite side of the home. My only question is, was this ever allowed in the past. Thanks, Mark

[Jerry Peck]

Typical meter can on the outside with no disconnect and SE cable running approximately 25 feet thru attic (not in conduit) and then down to main panel at opposite side of the home.

"Main panel"?

"Service equipment".


My only question is, was this ever allowed in the past.

Allowed by whom?

NEC? No.

By some jurisdictions as the didn't understand what the NEC allowed and prohibited? Yes.

Write it up as incorrect, that the "service equipment" (where the main service disconnect is) needs to be installed at the end of the house where the meter is, and that what are now "service entrance conductors" will need to be replaced with "feeder conductors" ... or ... place the existing service entrance conductors in a conduit and encase that in minimum 2" of concrete.

If the service entrance conductors were in conduit now, it still wouldn't be correct as they need to be encased in minimum of 2"of concrete.

Then understand that it is unlikely to be corrected - but that is your client's decision.

YOU want it in YOUR report.

[mark petty]

As always; thanks very much. Mark



"Main panel"?

"Service equipment".



Allowed by whom?

NEC? No.

By some jurisdictions as the didn't understand what the NEC allowed and prohibited? Yes.

Write it up as incorrect, that the "service equipment" (where the main service disconnect is) needs to be installed at the end of the house where the meter is, and that what are now "service entrance conductors" will need to be replaced with "feeder conductors" ... or ... place the existing service entrance conductors in a conduit and encase that in minimum 2" of concrete.

If the service entrance conductors were in conduit now, it still wouldn't be correct as they need to be encased in minimum of 2"of concrete.

Then understand that it is unlikely to be corrected - but that is your client's decision.

YOU want it in YOUR report.

[Jerry Peck]

Mark,

This may help when considering what things are:

There are two basic electrical system components:
- Service to the structure
- Premises wiring of the structure

The "service" starts at the utility transformer, overhead on a pole for overhead service or on a pad on the ground for underground service.

Overhead service has an overhead service drop to the structure; underground service has underground service lateral to the structure.

The "overhead service" consists of:
- service drop (utility owned)
- service entrance conductors (owned by the owner of the structure)
- through the meter (owner of structure owns the meter can/utility owns the meter)
- service entrance conductors (owned by the owner of the structure)
- service equipment where the main service disconnect is located (owned by the owner of the structure)

There is no 'supply side' (at the transformer) overcurrent protection of the service drop or the service entrance conductors all the way to, and through, the meter - the power company has a power cut out fuse before the transformer to protect the transformer (lineman call those "Jacks", it is a combination of fuse and switch, it blows open to protect the transformer).

The first overcurrent device is the main service disconnect 'at' the structure ... preferably 'outside' the structure ... but allowed to be a very short distance inside the structure after the 'point of entrance' where the service entrance conductors penetrate through the outside surface of the structure.

The main service disconnect is still part of the "service", thus it is "service equipment". Downstream of that main service disconnect is premises wiring, even if in the same enclosure (as would be the case when there is one electrical panel which contains the main service disconnect, bus bars with breakers for the circuits. Those electrical panels have two separate, but combined within the one enclosure, sections: service equipment to and including the main service disconnect; electrical panel for premises wiring is after the main service disconnect load terminals.

[mark petty]

WOW! great info


Mark,

This may help when considering what things are:

There are two basic electrical system components:
- Service to the structure
- Premises wiring of the structure

The "service" starts at the utility transformer, overhead on a pole for overhead service or on a pad on the ground for underground service.

Overhead service has an overhead service drop to the structure; underground service has underground service lateral to the structure.

The "overhead service" consists of:
- service drop (utility owned)
- service entrance conductors (owned by the owner of the structure)
- through the meter (owner of structure owns the meter can/utility owns the meter)
- service entrance conductors (owned by the owner of the structure)
- service equipment where the main service disconnect is located (owned by the owner of the structure)

There is no 'supply side' (at the transformer) overcurrent protection of the service drop or the service entrance conductors all the way to, and through, the meter - the power company has a power cut out fuse before the transformer to protect the transformer (lineman call those "Jacks", it is a combination of fuse and switch, it blows open to protect the transformer).

The first overcurrent device is the main service disconnect 'at' the structure ... preferably 'outside' the structure ... but allowed to be a very short distance inside the structure after the 'point of entrance' where the service entrance conductors penetrate through the outside surface of the structure.

The main service disconnect is still part of the "service", thus it is "service equipment". Downstream of that main service disconnect is premises wiring, even if in the same enclosure (as would be the case when there is one electrical panel which contains the main service disconnect, bus bars with breakers for the circuits. Those electrical panels have two separate, but combined within the one enclosure, sections: service equipment to and including the main service disconnect; electrical panel for premises wiring is after the main service disconnect load terminals.

[Ray Thornburg]

1983 block home on slab with overhead service: Typical meter can on the outside with no disconnect and SE cable running approximately 25 feet thru attic (not in conduit) and then down to main panel at opposite side of the home. My only question is, was this ever allowed in the past. Thanks, Mark

You'll see this sometimes on older homes. Now days they want the main disconnect to be as close as practical to where the service conductors enter the home.

[david shapiro]

To underscore Jerry's excellent "No, nay, never" response, my 1915 NEC says in Section 23 (1930s editions, Section 404): "CONSTANT-POTENTIAL SYSTEMS. General Rules--all voltages. 23. Automatic Cut-outs (Fuses and Circuit Breakers).
(See also No. 19. For construction rules see also Nos. 66 and 67.)
a. Must be placed on all service wires, either overhead or underground, in the nearest accessible place to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building. Departure from this rule may be authorized only under special permission in writing. . . ."

[Dwight Doane]

my 1915 NEC says in Section 23 (1930s editions, Section 404):

Where did you get this antique - Actually it's kind of nice to have to know when some rules started.

[Jerry Peck]

To underscore Jerry's excellent "No, nay, never" response, my 1915 NEC says in Section 23 (1930s editions, Section 404): "CONSTANT-POTENTIAL SYSTEMS. General Rules--all voltages. 23. Automatic Cut-outs (Fuses and Circuit Breakers).
(See also No. 19. For construction rules see also Nos. 66 and 67.)
a. Must be placed on all service wires, either overhead or underground, in the nearest accessible place to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building. Departure from this rule may be authorized only under special permission in writing. . . ."

To continue with David's reference (both continue with the reference and continue back in time):
Form my 1905 NEC:
(number 21 instead of 23)
a. Must be placed on all service wires, either overhead or underground, as near as possible to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building.
- Where the switch is required by No 22. is inside the building, the cut-out required by this section must be placed sa as to protect it.
In risks having private plants, the yard wwires running from building to building are not generally considered as service wires, so that cut-out would not be required where the wires enter buildings, provided that the next fuse back is small enough to properly protect the wires inside the building in question.

Stepping back further in time to the 1897 NEC:
(the number is 24, being as the 1897 NEC is considered "the first NEC", the number started as 24)
a. Must be placed on all service wires, either overhead or underground, as near as possible to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building, and must conform with Rule 17 a and 17* Sections

Rule 17 is "Switches, Cut-outs, Circuit Breakers, etc."

Rule 17* is "Cut-outs and Circuit Beakers."

Going back even further in time ... wait, if the 1897 NEC is "the first NEC" ... how can one go back further in time? I have a book printed in 1896 which contains the pre-published rules of that 1897 NEC. The wording in that book does not exactly match the 1897 wording, indicating that changes were made prior to the 1897 publication as "the" 1897 NEC (it was not called the "National Electrical Code" in 1897, it was the
Rules and Requirements
OF THE
Underwrites' Association
OF THE
Middle Department
FOR THE INSTALLATION OF
WIRING AND APPARATUS
FOR
LIGHT, HEAT AND POWER
Adopted August 31, 1897
SUPERSEDING ALL PREVIOUS RULES


From my 1896 book: (which states that the following is "The National Code is said to be the wireman's bible ; it says "thou shalt not use this, and thou shalt not do that," and it also contains for him who will study it, the principles which enables him to decide what he ought to do.")

National Board Fire Underwriters
Rules and Requirements of the Fire Underwriters for the Installation of Wiring and Apparatus for Electric, Light and Power as Recommended by the Underwriters' and National Electric Association

17. Inside Wiring - General Rules :
At the entrance of every building there shall be an approved switch placed in the service conductors by which the current may be entirely cut off. (See Definitions.)

So ... going back to 'Before Day One' of the NEC ... the 'service disconnect' (not yet call that) was required to be "at the entrance of every building".

[Jim Hintz]

Damn Jerry,
You're definitely the Historian of this Forum / Website, and, we appreciate you !

Jim