Article 225 Outside Branch Circuits and Feeders

225.1

Scope

This article covers feeders and branch circuits located outside on premises between buildings or poles, or for equipment on the outside of buildings or poles.

225.2

Other Articles

Table 225.2 refers to other articles in the Code which are pertinent to outside branch circuits and feeders.

Table 225.2. Other Articles

 

Article

Branch Circuits

210

Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits

725

Communications Circuits

800

Community Antenna Television and Radio Distribution Systems

820

Conductors for General Wiring

310

Electrically Driven or Controlled Irrigation Machines

675

Electric Signs and Outline Lighting

600

Feeders

215

Fire Alarm Systems

760

Fixed Outdoor Electric De-icing and Snow-Melting Equipment

426

Floating Buildings

553

Grounding

250

Hazardous (Classified) Locations

500

Hazardous (Classified) Locations, Specific

510

Marinas and Boatyards

555

Messenger Supported Wiring

396

Mobile Homes, Manufactured Homes, and Mobile Home Parks

550

Open Wiring on Insulators

398

Over 600 Volts, General

490

Overcurrent Protection

240

Radio and Television Equipment

810

Services

230

Solar Photovoltaic Systems

690

Swimming Pools, Fountains, and Similar Installations

680

Use and Identification of Grounded Conductors

200

 

I. General

225.3

Calculation of Loads 600 Volts, Nominal, or Less

Use 210.10 for outdoor branch circuits and Part III of Article 220 for outdoor feeders.

225.4

Conductor Covering

Conductors must be insulated or covered within 3 m (10 ft.) of a building. Conductors in raceways or cables except MI must have thermoplastic or rubber insulation. An exception is made for equipment grounding conductors and grounded circuit conductors. Section 310.8 governs wet locations.

225.5

Size of Conductors 600 Volts, Nominal, or Less

Size in accordance with Section 310.15. Determine loads in accordance with Section 220.10 and Part III of Article 220.

225.6

Conductor Size and Support

(A) Overhead Spans

600 V or less, up to 15 m (50 ft.): 10 AWG copper, 8 AWG aluminum except where supported by a messenger wire

600 V or less, over 15 m (50 ft.): 8 AWG copper, 6 AWG aluminum except where supported by a messenger wire

More than 600 V: 6 AWG copper, 4 AWG aluminum for open conductors; 8 AWG copper, 6 AWG aluminum for cable

(B) Festoon Lighting

Use 12 AWG or Larger for festoon lighting except where messenger wires support them, over 12 m (40-ft.) span require messenger wire support.

225.7

Lighting Equipment Installed Outdoors

225.10

Wiring on Buildings

225.11

Circuit Exits and Entrances

Refer to Sections 230.52, and 230.54.

225.12

Open Conductor Supports

225.14

Open Conductor Spacings

225.15

Supports Over Buildings

Refer to Section 230.29.

225.16

Attachment to Buildings

Refer to Sections 230.26 and 230.27.

225.17

Masts as Supports

225.18

Clearance from Ground

Open conductors and open multiconductor cables not over 600 V must conform to the following:

3 m (10 ft.): above finished grade: 150 V to ground

3.7 m (12 ft.): over residential driveways and commercial areas not subject to truck traffic: 300 V to ground limitation

4.5 m (15 ft.): same as 3.7 m (12 ft.) above: exceeding 300 V to ground

5.5 m (18 ft.): above streets, driveways, etc. subject to truck traffic as well as land used by vehicles such as forest, grazing, etc.

225.19

Clearances from Buildings for Conductors of Not over 600 Volts, Nominal

(A) Above Roofs. Not less than 2.5 m (8 ft.) vertical clearance from the roof surface maintained for a distance of not less than 900 mm (3 ft.) in all directions from the edge of the roof except the final span to the attachment to the building. If subject to pedestrian or vehicular traffic, vertical clearances should be in accordance with Section 225.18. Other exceptions are as follows:

900 mm (3 ft.) clearance: voltage between conductors not more than 300 V and roof slope is maximum of 100 mm (4 in.) in 300 mm (12 in.).

450 mm (18 in) clearance above the overhanging portion of the roof: voltage between conductors not more than 300 V, not more than 1.8 m (6 ft.) of conductor, 1.2 m (4 ft.) horizontally, do not pass over an overhang and are terminated in approved support or raceway through the roof.

900 mm (3 ft.) clearance does not apply to the final conductor span attached to the roof.

(B) From Nonbuilding or Nonbridge Structures. Clearances in all directions to be a minimum of 900 mm (3 ft.).

(C) Horizontal Clearances. Not less than 900 mm (3 ft.).

(D) Final Spans. Those may be attached to a building but must clear operable windows, fire escapes, and the like by at least 900 mm (3 ft.). If above the top level of a window then it can be reduced to less than 900 mm (3 ft.). There is additional information concerning openings in commercial buildings and vertical clearances.

(E) Zone for Fire Ladders. Allow for fire laddersat least a 1.8 m (6-ft.)-wide space.

225.20

Mechanical Protection of Conductors

Refer to Section 230.50.

225.21

Multiconductor Cables on Exterior Surfaces of Buildings

Refer to Section 230.51.

225.22

Raceways on Exterior Surfaces of Buildings, or Other Structures

They must drain and be raintight in wet locations other than flexible metal conduit as permitted in 348.12(1).

225.24

Outdoor Lampholders

225.25

Location of Outdoor Lampholders

225.26

Vegetation as Support

Not permitted.

II. More Than One Building or Other Source

225.30

Number of Supplies

Where you have more than one building under one management and on the same property you can only have one feeder or branch circuit from the service disconnect supplying each of the additional buildings. The exceptions are noted in (A) through (E).

(A) Special Conditions. You can have additional feeders or branch circuits for fire pumps, emergency systems, legally required standby systems, parallel power production systems, optional standby systems, and systems connected to multiple sources of supply for greater reliability.

(B) Special Occupancies. In a single building where the load is too large for one feeder or branch circuit or in multi-occupancy buildings where there is no space for supplies accessible to all occupants then with special permission you can have additional feeders or branch circuits.

(C) Capacity Requirements. If the load requirements are more than 2000 A and the voltage is not more than 600 V, more than one supply is allowed.

(D) Different Characteristics. More than one supply is allowed if different characteristics, i.e., voltage, frequency, etc. are required.

(E) Documented Switch Procedures. You can have more than one supply if they are under one management and there are documented safe disconnecting procedures.

225.31

Disconnecting Means

Must be provided.

225.32

Location

It must be located at the poiint where the wire passes through the building either inside or outside. It must be readily accessible. You are allowed to use the requirements of Section 230.6. There are four exceptions.

225.33

Maximum Number of Disconnects

The provision for disconnecting each supply in 225.30 can consist of no more than six switches or six circuit breakers. Single-pole units can be used on multiwire circuits, one pole for each ungrounded conductor. They must be tied together as a multipole disconnect and will then be counted as one disconnect. An exception is made for the control circuit of a ground-fault protection system or the control circuit of the power operated supply disconnecting means.

225.34

Grouping of Disconnects

All disconnects are to be grouped together. An exception is made for fire pumps. The disconnects for fire pumps, emergency legally required standby or optional standby systems must be located away from the normal supply.

225.35

Access to Occupants

Must be accessible to the occupants except where there is a single management with continuous supervision.

225.36

Suitable for Service Equipment

225.37

Identification

225.38

Disconnect Construction

225.39

Rating of Disconnect

In general, the feeder or branch circuit disconnect must be sized to carry the calculated load as determined in accordance with Article 220. There are special cases where a minimum size is required. They are:

15 A: a single branch-circuit load.

30 A: up to two, two-wire branch circuits

100 A: three-wire: one-family dwelling with six or more two-wire branch circuits or calculated load is 10 kW or more.

60 A: all others.

225.40

Access to Overcurrent Protective Devices

 

III. Over 600 Volts

225.50

Sizing of Conductors

225.51

Isolating Switches

225.52

Locations

225.53

Type

225.60

Clearances over Roadways, Walkways, Rail, Water, and Open Land

225.61

Clearances over Buildings and Other Structures






Pocket Guide to the National Electrical Code 2005
Pocket Guide to the National Electrical Code(R), 2005 Edition (8th Edition)
ISBN: 0131480014
EAN: 2147483647
Year: 2004
Pages: 120
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