1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2009 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA)
4、 Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSURFACEVEHICLESTANDARDJ2120 NOV2009 Issued 1992-07Reaffirmed 2009-11 Superseding J2120 AUG2008 Personal WatercraftElectrical Systems RATIONALESAE Personal Watercraft Recommended Practice J2120 was finalized in July 19
5、97. It has been widely accepted by the Personal Watercraft industry and used as a guide towards standard engineering practice since its inception. It is part of the certification criteria of the National Marine Manufacturers Association Personal Watercraft Certification Program and has become a tech
6、nical reference within ISO 13590 Personal Watercraft Construction and System Installation Requirements. As a result of this activity, the Recommended Practice classification of this SAE Technical Report can be upgraded to the Standard level. 1. SCOPE This SAE Standard applies to personal watercraft
7、as defined in Section 3. With the exception of Sections 5 and 6, this document does not apply to electronic circuits having a current flow of less than 1 A; conductors which are totally inside an equipment housing; resistance conductors that control circuit amperage; high-voltage secondary conductor
8、s and terminations that are in ignition systems; pigtails of less than 180 mm of exposed length; and cranking motor conductors. 1.1 Purpose This document specifies construction and performance guidelines for electrical systems of personal watercraft. It is intended as a guide toward standard practic
9、e and is subject to change to keep pace with experience and technical advances.2. REFERENCES 2.1 Applicable Publications The following publications form a part of this specification to the extent specified herein. The latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available fro
10、m SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J378 Marine Propulsion System Wiring SAE J1127 Low Voltage Battery Cable SAE J1128 Low Voltage Primary Cable SAE J2031 High Tension Ignitio
11、n Cable SAE J2120 Reaffirmed NOV2009 Page 2 of 63. DEFINITIONS 3.1 AWG American Wire Gauge. 3.2 Conduit Any type of rigid plastic or metal piping or tubing which supports the conductors contained within. 3.3 Electrical Component Electrical equipment such as, but not limited to, conductors, solenoids
12、, motors, alternators, distributors, resistors, and electrical control devices. 3.4 High Voltage Circuit A nominal voltage of 50 V or more. 3.5 Ignition Protection The design and construction of a device such that under design operation conditions it will not ignite a flammable hydrocarbon mixture s
13、urrounding the device when an ignition source causes an internal explosion, or it is incapable of releasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture, or the source of ignition is hermetically sealed.3.6 Low Voltage Circuit A nominal voltage of less than 50 V. 3.7 Perso
14、nal Watercraft A vessel less than 4 m (13 ft) in length which uses an internal combustion engine powering a water jet pump as its primary source of propulsion, and is designed to be operated by a person or persons sitting, standing, or kneeling on rather than within the confines of a hull. 3.8 Pigta
15、il External power conductors or wires that are part of electrical components such as bilge pumps, blowers, switches, solenoids, and fuses. 3.9 Sheath A material used as a continuous protective covering, such as electrical tape, molded rubber, molded plastic, or flexible tubing, around one or more in
16、sulated conductors. 4. CONDUCTOR TYPE, SIZE, AND IDENTIFICATION 4.1 Each conductor must be insulated, stranded copper. 4.2 Low-voltage conductors shall comply with SAE J378b, SAE J1127, SAE J1128, or equivalent standards. 4.3 No conductor shall be used to carry an amperage greater than that specifie
17、d in Table 1 for its gauge. The ampacity of conductors in an engine compartment must be corrected by the appropriate factor indicated in Table 1. 4.4 A means of identification shall be used to distinguish individual conductors. SAE J2120 Reaffirmed NOV2009 Page 3 of 65. CONDUCTOR SUPPORT AND PROTECT
18、ION 5.1 Each conductor shall be installed so that it is protected from physical damage. Except for the first 500 mm of battery cables, conductors shall be supported by clamps or straps not more than 400 mm apart unless the conductor(s) is contained in a conduit. 5.2 Clamps, straps, or conduits shall
19、 be designed to prevent damage to the conductor insulation. 5.3 Conductors connecting components that can move with relation to each other shall be protected from stress. 5.4 Conductors passing through bulkheads, junction boxes, or other rigid surfaces shall be bushed with conduit or grommets, or th
20、e conductor shall be protected by a sheath. 6. EXTERNAL IGNITION PROTECTION A representative electrical system as installed in the watercraft, or in an enclosure simulating the watercraft, must not ignite a propane gas and air mixture that is 4.25 to 5.25% propane gas by volume surrounding the elect
21、rical system when it is operated in the mode in which it draws its maximum current. The test voltage supply shall be adjusted to 120% of the nominal system voltage except magneto ignition systems. TABLE 1 - MAXIMUM CURRENT OF CONDUCTORS (AMPERAGE) TEMPERATURE RATING OF CONDUCTOR INSULATION (AWG)Wire
22、 Size 60 C (140 F) 75 C (167 F) 80 C (178 F) 90 C (194 F) 105 C (221 F)125 C (257 F) 200 C (392 F) 18 10 10 15 20 20 25 25 16 15 15 20 25 25 30 35 14 20 20 25 30 35 40 45 12 25 25 35 40 45 50 55 10 40 40 50 55 60 70 70 8 55 65 70 70 80 90 100 6 80 95 100 100 120 125 135 4 105 125 130 135 160 170 180
23、 3 120 145 150 155 180 195 210 2 140 170 175 180 210 225 240 1 165 195 210 210 245 265 280 0 195 230 245 245 285 305 325 10 225 265 285 285 330 355 370 100 260 310 330 330 385 410 430 1000 300 360 385 385 445 475 510 ENGINE COMPARTMENT CORRECTION FACTORS 0.56 0.75 0.78 0.82 0.85 0.89 1.00 SAE J2120
24、Reaffirmed NOV2009 Page 4 of 67. OVERCURRENT PROTECTION 7.1 Except for conductors from self-limiting generators or alternators, each ungrounded current-carrying conductor shall be protected by a manually reset, trip-free circuit breaker or fuse. The fuse or breaker shall be within 180 mm of the orig
25、in of the conductor to be protected so long as the fuse or breaker is sized for the smallest conductor in the circuit. 7.1.1 Exception 1 If a conductor is continuously protected from physical damage by a sheath or enclosure between its terminal ends, the maximum distance to its protecting fuse or br
26、eaker may be increased to 500 mm from the power source measured along the conductor. 7.1.2 Exception 2 An ungrounded supply conductor starting at a storage battery must have its breaker or fuse within 900 mm of the battery measured along the conductor Figure 1. 7.2 The voltage rating of each circuit
27、 breaker or fuse shall not be less than the nominal voltage of the circuit it is protecting.7.3 The current ratings of the circuit breaker or fuse shall not be more than 150% of the value in Table 1 for the conductor it is protecting including the correction factor if any part of the conductor is in
28、 an engine compartment. FIGURE 1 - BREAKER/FUSE LOCATION FOR AN UNGROUNDED SUPPLYCONDUCTOR STARTING AT A STORAGE BATTERY 7.4 Circuit breakers or fuses for non-self-limiting generators and alternators shall have a current rating not exceeding 120% of the maximum rated output at 60 C. 8. CONDUCTOR TER
29、MINATIONS 8.1 All connections outside of junction boxes or enclosures shall be made with closed ring, eyelet, captive spade, or mechanical or spring lock type connectors. Wire nuts shall not be used on any connection. SAE J2120 Reaffirmed NOV2009 Page 5 of 68.2 Single or multi-connector plugs outsid
30、e of junction boxes or enclosures shall not separate under an axial load of 2.7 kg applied for 1 min. 8.3 A soldered joint must not be the sole means of connection to any conductor except for battery terminal connectors with soldered joints at least 1.5 times longer than the diameter of the conducto
31、r strands. 8.4 Conductor splices and joints to connectors outside of junction boxes or enclosures shall not break when subjected for 1 min to the load shown in Table 2 for the smallest conductor in the connection. 8.5 Ungrounded terminal fittings and conductors shall be protected from accidental sho
32、rt circuiting with grounded metal or other ungrounded circuits in the event a termination should loosen. Continuously energized terminations without circuit protection must be covered with boots or equivalently protected. 9. BATTERIES 9.1 Each installed battery must not move more than 25 mm in any d
33、irection when a pulling force of twice the battery weight is applied through the center of gravity of the battery as follows: 9.1.1 Vertically in both directions for a duration of 1 min. 9.1.2 Horizontally and parallel to the watercrafts centerline for a duration of 1 min fore and 1 min aft. TABLE 2
34、 - TENSILE TEST VALUES FOR WIRE SPLICES (CONDUCTOR-CONDUCTOR AND CONDUCTOR-CONNECTOR JOINTS) Wire Size (AWG)Tensile Force (kilograms)18 4.5 16 6.5 14 13.5 12 16 10 18 8 20.5 6 22.5 5 27 4 32 3 36 2 41 1 45.5 9.1.3 Horizontally and perpendicular to the watercrafts centerline for a duration of 1 min t
35、o starboard and 1 min to port. 9.2 Each battery must be installed so that metallic objects cannot come in contact with the ungrounded battery terminals.9.3 Each metallic fuel line and fuel system component within 100 mm and above the horizontal plane of the battery top surface as installed must be s
36、hielded with dielectric material. 9.4 Each battery must not be directly above or below a fuel tank, fuel filter, or fitting in a fuel line. 9.5 A vent system or other means must be provided to permit the discharge from the watercraft of hydrogen gas released by the battery. 9.6 Each battery terminal
37、 connector must not depend on spring tension for its mechanical connection to the terminal. SAE J2120 Reaffirmed NOV2009 Page 6 of 610. SECONDARY CIRCUITS OF IGNITION SYSTEMS 10.1 Each conductor in a secondary circuit of an ignition system shall meet SAE J2031 or equivalent standards. 10.2 The conne
38、ction of each ignition conductor to a spark plug, coil, or distributor must have a tight fitting cap, boot, or nipple.11. NOTES 11.1 Marginal Indicia A change bar (I) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, hav
39、e been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE PERSONAL WATERCRAFT SUBCOMMITTEEOF THE SAE MARINE TECHNICAL COMMITTEE REAFFIRMED BY THE SAE PERSONAL WATERCRAFT COMMITTEE OF THE SAE SPECIALIZED VEHICLE AND EQUIPMENT COUNCIL
