20-33-30 Page 5
To avoid chafing, the size of the conduit must be determined to
obtain the maximum permissible fill factor.
The modification could use this spare space.
-
For split conduits, a minimum overlap of 45. is mandatory (maximum 135.). A greater overlap is used to add cables.
-
For heat-shrinkable conduits, the size depends on the bundle diameter.
20-33-30 Page 6
Apr 01/04
R (3) Length
(Ref. Fig. 001) R - The conduit length is not mandatorily the same as the harness R length but only the length which could be damaged.
-The use of convoluted conduits greater than 3500 mm (137.7953 in.) is not recommended.
-Sufficient slack should be left between the conduit extremity and the electrical aquipment to prevent strain to connection, to minimize rubbing on shock-mounted equipment or reduction of the insulation characteristics by liquid accumulation in the conduit at the rear of the connector.
-A conduit length of 10 mm (0.3937 in.) to 15 mm (0.5905 in.) must be observed at each extremity from the last attachment.
20-33-30 Page 7
C. Attachment (Ref. Fig. 001) Conduits should be supported by use of cable supports along the conduit run. As a general rule, attachment P/Ns are given in the IPC. However,
R check the installation type on the basis of the following points:
____
NOTE : Attachment selection also depends on the cable support selection depending on the area. For more information, refer to chapter 20-33-4X - Bundle attachments
-For bundles protected with convoluted conduit E0432, NSA935805 or NSA935806, attachment on the structure is performed by means of "P" clamps NSA935807 and at the rear of the connector by means of cable tie NSA935401 (take care that the cable tie, when tightened, does not excessively crush the conduit).
-The clamp must ensure the correct tightening of the bundle in order to prevent fretting by chafing of the conduit. It should not allow the bundle to move through the clamp when slight axial pull is applied.
-Make sure that the conduit attachment is correct.
____
NOTE : If a clamp of the correct size cannot be obtained, a clamp of slightly greater diameter than that of the wire bundle to be attached must be selected, and to obtain a normal grip of the clamp in all areas, wrap self adhesive silicone tape ASNA5107 around the conduit.
____
NOTE : It is prohibited to try to distribute the over length by pulling on the bundle when the clamps or other cable attachments are gripped.
20-33-30 Page 8
-------------------------------------------------------------------------------| USING |CONDUIT TYPE | METHOD | |--------------------------|-------------|--- --------------------------------| | | | <<P>> clamp NSA935807 with | | | | washer NSA935808 | | | |------------------------------------| | Along conduit run | | Only conduit size > 24: | | | | Cable support NSA935504 with | | | | cable tie NSA935401 | | | | (installation not preferred) | |--------------------------| |------------------------------------| | | | Only carbon fuel tank : | | | Convoluted | Clamp NSA5515 + bobbin NSA935809 | | Conduit extremity | conduit |------------------------------------| | (last attachment) | | Clamp NSA935813 + bobbin NSA935809 | | | |------------------------------------| | | | Clamp type NSA5516 | |--------------------------| |------------------------------------| | Bundle hinge | | Clamp type NSA5516 | |--------------------------| |------------------------------------| | | | Only carbon fuel tank: | | | | Clamp NSA5515 + bobbin NSA935809 | | Last attachment point | |------------------------------------| | before connection | | Clamp NSA935813 + bobbin NSA935809 | | | |------------------------------------| | | | Clamp type NSA5516 | | | | (installation preferred) | |--------------------------|-------------|------------------------------------| | Metallic structure | | Clamp type NSA5516 | |--------------------------| |------------------------------------| |Wiring of M and S route in| Metallic | | | non metallic structure | conduit | Clamp type NSA5516 | | (carbon) | | | |--------------------------| |------------------------------------| | For intermediate bonding | | Clamp type NSA5516 + ASNA0182 | |--------------------------|-------------|------------------------------------| | All areas | Flexible | Clamp type NSA5516 or V cable | | | conduit | support | -------------------------------------------------------------------------------
20-33-30 Page 9
Apr 01/04
R ______________3. Main Procedure
A. Draw wire (Ref. Fig. 002) A draw wire is an 18 gauge electric wire placed inside all conduits in which it would be difficult to introduce an additional wire directly. It is recommended when the conduit length is greater than 50 mm (1.9685 in.) (except for conduits where all the cables have a disconnectable termination such as connectors, terminal blocks, etc...). The draw wire shall protrude at least 100 mm (3.9370 in.) from both ends of the conduit. Each end of the draw wire shall be insulated with a heat shrink sleeve or a crimped insulating cap (e.g. NSA936601) in order not to damage the other cables. A sleeve marked "DRAW WIRE" shall be installed at each end in order to differentiate it from the other cables. Each end of the draw wire will be folded on the conduit and tie.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：A320 ESPM Electrical Standard Practices Manual 2(54)
