Article 225 Outside Branch Circuits and Feeders

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.

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

I. General

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

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.

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

(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.

Refer to Sections 230.52, and 230.54.

Refer to Section 230.29.

Refer to Sections 230.26 and 230.27.

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.

(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.

Refer to Section 230.50.

Refer to Section 230.51.

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

Not permitted.

II. More Than One Building or Other Source

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.

Must be provided.

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.

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.

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.

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

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.

III. Over 600 Volts