7 C.F.R. § 1755.910
(a) Scope.
(b) General information.
(c) General documentation requirements—(1) Installation and maintenance instructions.
(3) RUS acceptance applications.
(ii) For initial acceptance the manufacturer shall:
(d) Functional design criteria for housings—(1) General requirements.
(2) Housing types and capacities.
(ii) The classifications of pedestals are the general purpose channel Type (H) and the dome Type (M). The Type H pedestal has either front only access or back and front access while the Type M pedestal has top only access. Pedestals are further designated as follows:
| Stake mounted | Type | Pole mounted | Pole mounted (extra high) |
|---|---|---|---|
| BD3 | H | BD3A | |
| BD4 | H | BD4A | |
| BD5 | H | BD5A | |
| BD7 | H | BD7A | |
| BD14 | M | BD14A | BD14AG |
| BD15 | M | BD15A | BD15AG |
| BD16 | M | BD16A | BD16AG |
(iii) The minimum volume associated with the pedestal designations shall be as shown in the following table:
| Pedestal 1 housing designation | Minimum volume | |
|---|---|---|
| Cubic centimeters cm 3 | (Cubic Inches) (in.3) | |
| BD3, BD3A 2 | 9,000 | (550) |
| BD4, BD4A 2 | 15,000 | (900) |
| BD5, BD5A 2 | 35,000 | (2,100) |
| BD7( 2 ) | 72,000 | (4,400) |
| BD14, BD14A, BD14AG 3 | 9,000 | (550) |
| BD15, BD15A, BD15AG 3 | 27,000 | (1,600) |
| BD16, BD16A, BD16AG 3 | 38,000 | (2,300) |
| Note 1: Housings designed for unique purposes will be evaluated on a case-by-case basis. | ||
| Note 2: For Type H pedestals, the minimum volume is that space as measured 5 centimeters (cm) (2 inches (in.)) below the top of the housing to a point 40 cm (16 in.) above the bottom of the lower cover plate. | ||
| Note 3: The minimum volume of the Type M pedestals shall be the space within the dome measured from the lower edge of the dome to a point 5 cm (2 in.) from the top. |
(vi) The minimum volume associated with large pair count splice cabinets shall be as shown in the following table:
| Splice cabinet 1 designation | Minimum volume | Maximum splice capacity (pairs) | |
|---|---|---|---|
| (cm.3) | (in.3) | ||
| BD6000 | 295,000 | (18,000) | 6,000 |
| BD8000 | 393,000 | (24,000) | 8,000 |
| BD10000 | 491,000 | (30,000) | 10,000 |
| Note 1: Additional sizes of splice cabinets shall be considered by RUS on a case-by-case basis. |
(3) Design and fabrication requirements for housings.
(4) Warning sign.
(5) Housing materials.
(i) Materials used in housings shall present no environmental or safety hazard as defined by industry standards or Federal, State, or local laws and regulations. Figure 1 is as follows:

(vi) Mill galvanized steel used in the manufacture of housings shall comply with the appropriate requirements of one of the following standards:
(vii) Hot rolled steel shall comply with the appropriate requirements of one of the following standards:
(viii) Cold rolled steel shall comply with the appropriate requirements of one of the following standards:
(6) Housing finish requirements.
(v) The colors of housings that RUS will consider for acceptance shall be as follows:
| Color | Standard |
|---|---|
| Gray-Green | Munsell 6.5 GY 6.03/1.6 |
| Munsell 4.4 GY 6.74/1.5 | |
| Green | Munsell 8.8 G 2.65/5.3 |
| Orange | Federal Standard 595A |
| Color Number l2246 | |
| Munsell 0.15YR 5.26/13.15 | |
| Chocolate | Munsell 5.27YR 2.40/2.60 |
| Color Number 835 |
(7) Installation requirements.
(e) Performance criteria and test procedures for housings—(1) General information.
(2) Description of test housing.
(3) Environmental requirement for housings—(i) Thermal shock. The test housing shall be placed in a test chamber and exposed to the temperature cycle of Figure 2 for five complete cycles. The step function nature of the temperature changes may be achieved by insertion and removal of the test housing from the chamber. The soak time at each temperature shall be four hours. The housing shall be removed from the test chamber at the conclusion of the five-cycle period. After the test housing temperature has stabilized to room temperature, the housing must be inspected for deterioration of materials and satisfactory operation of mechanical functions. Figure 2 is as follows:

(ii) Thermal shock and humidity. The test housing shall be placed in an environmental test chamber at 95 ±3 percent (%) relative humidity (RH) and temperature cycled per Figure 3 for a period of 30 days. At the end of the test there shall be no rust or corrosion of any closure components. Minor corrosion due to surface scratches, nicks, etc. is permitted. If the closure is made of a nonmetallic material, there shall be no signs of degradation. Figure 3 is as follows:

(v) Low temperature durability. Low temperature durability shall be proven by exposing the three test panels from (e)(3)(iv) of this section to at least 25 continuous cycles of the following test sequence:
(viii) Stress crack resistance. The stress cracking characteristics of nonmetallic housing components shall be tested in accordance with ASTM D 1693-70 (Reapproved 1988). The tests shall be performed at 49±2 1/2 C (120±4 1/2 F) for 14 days and exposed to the following materials:
(ix) Chemical resistance.
(A) Chemical resistance shall be determined by immersing representative nonmetallic material samples in each of the following solutions for 72 hours at 22±2 °C (71.6±4 °F):
(1) 3% sulfuric acid;
(2) 100 parts per million (ppm) trichloroethane in water;
(3) 0.2 N sodium hydroxide; and
(4) Unleaded high octane gasoline.
(xii) Wind Resistance.
(A) (1) Stub pole or wall mounted SAI and large pair count splice housings shall be subjected to a load (F) as shown in Figure 4 and the following table to simulate the turning moment equivalent to a uniform wind load of 161 kilometers per hour (km/h) (100 miles per hour (mi/h)) perpendicular to the largest surface area.
| Maximum area of largest surface square centimeters cm2(Square inches) (in.2) | Load | |
|---|---|---|
| kg | (lb) | |
| 5,200 (800) or less | 18 | (40) |
| 5,201 to 9,100 (801 to 1,400) | 32 | (70) |
| 9,101 to 13,000 (1,401 to 2,000) | 45 | (100) |
| 13,001 to 16,200 (2,001 to 2,500) | 57 | (125) |
| Note: The procedures for housings with larger surface area will be evaluated by RUS on a case-by-case basis. |
(2) The housing shall remain in its original mounting position throughout the test and exhibit no mechanical deformation.
(3) Figure 4 is as follows:

(B) (1) Pad or ground mounted SAI or splice housings shall be subjected to a load (F) as shown in Figure 5 and the following table to simulate the overturning moment equivalent to a uniform wind load of 161 km/h (100 mi/h) perpendicular to the largest surface area.
| Height cm (in.) | Maximum area of largest surface cm2 (in.2) | Load | |
|---|---|---|---|
| kg | (lb) | ||
| 122 (48) or less | 11,000 (1,700) or less | 91 | (200) |
| 11,001-13,000 (1,701-2,000) | 104 | (230) | |
| 13,001-14,900 (2,001-2,300) | 118 | (260) | |
| 123-152 (49-60) | 11,700 (1,800) or less | 91 | (200) |
| 11,701-14,300 (1,801-2,200) | 109 | (240) | |
| 14,301-16,200 (2,201-2,500) | 127 | (280) | |
| 16,201-18,800 (2,501-2,900) | 145 | (320) | |
| 18,801-20,800 (2,901-3,200) | 163 | (360) | |
| 20,801-23,400 (3,201-3,600) | 181 | (400) | |
| 153-183 (61-72) | 14,300 (2,200) or less | 109 | (240) |
| 14,301-16,900 (2,201-2,600) | 127 | (280) | |
| 16,901-19,500 (2,601-3,000) | 150 | (330) | |
| 19,501-22,700 (3,001-3,500) | 172 | (380) | |
| 22,701-25,300 (3,501-3,900) | 190 | (420) | |
| 25,301-27,900 (3,901-4,300) | 213 | (470) | |
| Note: The procedures for housings with larger surface areas will be evaluated by RUS on a case-by-case basis |
(2) The housing shall remain in its original mounting position throughout the test and exhibit no mechanical deformation.
(3) Figure 5 is as follows:

(xiii) Fire resistance.
(4) Mechanical requirements for housings—(i) Impact resistance. The test housing shall be subjected to the following impacts according to its minimum volume or minimum width and depth as shown in the following table:
| Minimum volume cm3 (in.3) | Minimum width or depth cm (in.) | Impact force | |
|---|---|---|---|
| N-m | (lb-ft) | ||
| Less than 35,000 (2,100) | Less than 13 (5) | 68 | (50) |
| 35,000 (2,100) or greater | 13 (5) or greater | 136 | (100) |
(ii) Load deflection. Free standing buried plant housings shall be tested for load deflection in accordance with Figure 6. The assembled housing shall be rigidly held in place by a mechanical means to simulate a normal field installation. A length of wire or cable, or other suitable material, shall be placed around the top section of the housing and deadended. The wire or cable shall be initially tensioned to 23 kg (50 lb). A measurement shall then be taken of the deflection of the housing at the top as shown in Figure 6. The deflection shall be recorded at incremental loads of 23 kg (50 lb) until destruction of the housing occurs. The average load for the three directions shall not be less than 136 kg (300 lb) and the minimum load in any direction shall be 113 kg (250 lb). Failure is defined as housing component fracture or crazing of the housing's surface finish. Figure 6 is as follows:

(iii) Vibration requirements. The test housing and its contents shall be subjected to acceleration at a sine wave frequency sweep rate as shown in Figure 7 for a housing packaged for shipment and Figure 8 for an unpackaged housing. The frequency sweep may be performed continually or sequentially. The test shall be conducted once along each of three mutually perpendicular axes of the housing. There shall be no mechanical or electrical degradation of the housing or its contents. Noticeable damage to the housing constitutes failure. Figure 7 and Figure 8 are as follows:


(iv) Drop test requirements. Housings shall be subjected to appropriate drop tests according to their weight. The drop tests shall be performed on housings and their contents as normally packaged as well as on unpackaged housings. The tests shall be conducted on a smooth level concrete floor or similar unyielding surface. For corner drops, the packaged housing and its contents shall be oriented at impact such that a straight line drawn through the struck corner and package geometric center is approximately perpendicular to the impact surface.
(A) Packaged housings and their contents weighing 91 kg (200 lb) or less shall be capable of enduring a single drop on each face or corner without damage from a height specified as follows:
| Packaged housing including contents weight kg (lb) | Drop height cm (in.) |
|---|---|
| 0 to 9 (0 to 20) | 76 (30) |
| 10 to 23 (21 to 50) | 61 (24) |
| 24 to 45 (51 to 100) | 53 (21) |
| 46 to 91 (101 to 200) | 46 (18) |
(B) Packaged housings and their contents weighing more than 91 kg (200 lb) shall be capable of enduring a single drop on each of two diagonally opposite corners of the package without significant damage from a height specified as follows:
| Packaged housing including contents weight kg (lb) | Drop height cm (in.) |
|---|---|
| 92 to 453 (201 to 1000) | 30 (12) |
| Over to 453 (1000) | 15 (6) |
(1) The packaged housing and contents shall be placed on its normal shipping base with one corner supported 15 cm (6 in.) above the floor and the other corner of the same end supported 30 cm (12 in.) above the floor as shown in Figure 9. The unsupported end of the package shall be raised so that the lowest corner reaches the height listed above and then allowed to fall freely. Figure 9 is as follows:

(2) The procedure of paragraph (e)(4)(iv)(B)(1) of this section shall be repeated for the diagonally opposite corner.
(3) The packaged housing and contents shall be capable of enduring a single drop on each edge of the base of its normal shipping position from the required height without damage and shall remain operational without function impairment. The packaged housing and contents shall be placed on its base with one edge supported on a sill 15 cm (6 in.) high and the unsupported edge raised to the required height as shown in Figure 10 and allowed to fall freely. Figure 10 is as follows:

(4) The procedure of (e)(4)(iv)(B)(3) of this section shall be repeated for all edges of the base.
(C) Unpackaged housings and their contents weighing 23 kg (50 lb) or less shall be capable of enduring a single drop on each face and adjacent corners without significant damage from a height specified as follows:
| Packaged housing including contents weight kg (lb) | Drop height cm (in.) |
|---|---|
| 0 to 9 (0 to 20) | 10 (4) |
| 10 to 23 (21 to 50) | 8 (3) |
(D) (1) Unpackaged housings and their contents weighing more than 23 kg (50 lb) shall be capable of enduring a single drop without significant damage when lifted by its normal hoisting supports as shown in Figure 11 and with its lowest point at a height specified as follows:
| Packaged housing including contents weight kg (lb) | Drop height cm (in.) |
|---|---|
| 23 to 45 (51 to 100) | 5 (2) |
(2) Figure 11 is as follows:

(viii) Door restrainer evaluation.
(A) The housing shall be positioned with the door held in the open position by the door restraining device. A load, determined in accordance with the following table, shall be applied to the center of the door, perpendicular to the door and in each of the opening and closing directions.
| Maximum area of door surface cm2 (in2.) | Loadkg (lb) |
|---|---|
| 5,200 (800) or less | 72 (160) |
| 5,201 to 9,100 (801 to 1,400) | 127 (280) |
| 9,101 to 13,000 (1,401 to 2,000) | 181 (400) |
| Note: Test procedures for housings with larger doors will be evaluated by RUS on a case-by-case basis. |
(2) Design and fabrication requirements.
(3) Auxiliary features.
(iv)
(A) A supply of twisted pair cross-connect wire shall be supplied with housings that are equipped with cross-connect terminals or that have provisions for mounting cross-connect terminals. The minimum length of cross-connect wire supplied is dependent on the SAI cabinet terminal capacity as follows:
| Cabinet termination capacity (pairs) | Wire length |
|---|---|
| 1 to 600 | 60 m (200 ft) |
| 601 to 1200 | 120 m (400 ft) |
| Over 1200 | 180 m (600 ft) |
(2) Environmental requirements—(i) Insulation resistance/high humidity and salt fog exposure. A test specimen shall consist of a standard ground or pole mounted housing equipped with a full complement of binding post terminals equipped with 25 special service markers. The minimum number of terminals to be tested shall be 100 pair (100 tips and 100 associated rings). The test terminals shall be selected to form a terminal array of approximate square dimensions. A 1 cm (36 in.) length of cross-connect wire shall be installed on each test terminal. All tips shall be joined together and all rings shall be joined together with a 48 volt dc potential applied as shown in Figure 12 during the high humidity/salt fog and simulated rain exposures. The 48 volt dc may be temporarily removed from the test samples during the measurement process and the ring terminal being measured shall be isolated from the remaining ring terminals. The terminal insulation resistance shall be measured at a potential of 100 volts dc using suitable instrumentation with a minimum measurement range of 10 4 to 10 12 ohms. Figure 12 is as follows:

(ii) Insulation resistance/simulated rain exposure.
(iii) Contact resistance. A minimum of 100 terminals equipped with cross-connect wire that has been installed in a manner typical of that used in the industry shall be temperature cycled.
(ii) Torsional capacity of binding posts. The test specimens shall consist of the complete binding post terminal consisting of the screw or nut, washers if required, and threaded post or stud respectively.
(iii) Lateral loading capacity of binding posts. A minimum of three sets of 25 terminals shall be tested with the test specimens stabilized at temperatures of −40 °C, 20 °C and 71 °C (−40 °F, + 68 °F, and 100 °F). The test arrangement shall include the terminals along the matrix edge at mid-span locations as well as centrally located terminals. A force measuring device, such as a dynamometer, shall be attached to the end of a binding post terminal and a 16 kg (35 lb) force applied orthogonally to the terminal axis in 4 perpendicular directions as shown in Figure 13. Permanent deformation in excess of 0.08 cm (0.03 in.) or any structural damage in either the terminal or faceplate constitutes a failure. Figure 13 is as follows:

(iv) Axial pullout resistance. A minimum of three sets of 25 terminals shall be tested with the test specimens stabilized at temperatures of −40 °C, 20 °C, and 71 °C (−40 °F, + 68 °F, and 100 °F). The test arrangement shall include the terminals along the matrix edge at mid-span locations as well as centrally located terminals. A force measuring device, such as a dynamometer, shall be attached to a terminal and a force of 16 kg (35 lb) applied on axis as shown in Figure 14. There shall be no permanent deformation in excess of 0.08 cm (0.03 in.), any structural damage, or terminal pull-out in either the terminal or the faceplate. Figure 14 is as follows:

(v) Test connector reliability.
(2) Design and fabrication requirements.
(3) Auxiliary features.
(2) Environmental requirements.
(j) Packaging and identification requirements—(1) Product identification.
(2) Packaging requirements.
(3) Container marking requirements.
(v) All marking shall be clear, legible, and as large as space permits.
(The information and recordkeeping requirements of this section have been approved by the Office of Management and Budget under control number 0572-0059)
[59 FR 53044, Oct. 21, 1994, as amended at 69 FR 18803, Apr. 9, 2004]