Bsi bs au 194 1984 (2000)

BRITISH STANDARD AUTOMOBILE SERIES

Specification for

Performance of
electrical connections
between towing
vehicles and trailers

UD C 62 9 . 1 1 . 0 1 3 . 5 : 62 1 . 3 1 6. 5 41

BS AU
194:1984


BS AU 194:1984

Committees responsible for this
British Standard
The preparation of this British Standard was entrusted by the Automobile
Standards Committee (AUE/- ) to Technical Committee AUE/1 6 upon which
the following bodies were represented:
Association of Trailer Manufacturers
Department of Transport
Electric Cable Makers’ Confederation
National Caravan Council Limited
Society of Motor Manufacturers and Traders Limited

This British Standard, having
been prepared under the
direction of the Automobile

Standards Committee, was
published under the authority
of the Board of BSI and comes
into effect on
31 January 1 984
© BSI 02- 2000

The following BSI references
relate to the work on this
standard:
Committee reference AUE/1 6
Draft for comment 77/73236 DC

ISBN 0 580 13542 X

Amendments issued since publication
Amd. No.

Date of issue

Comments


BS AU 194:1984

Contents
Page
Committees responsib le
Foreword

ii

1

Scope

1

2

Performance

1

Appendix A Tests
Pub lications referred to

© BSI 02 - 2 000

Inside front cover

2
Inside back cover

i


BS AU 1 94 : 1 984

Fore word

This British Standard has been prepared under the direction of the Automobile

“Road vehicles — Electrical
connections between towing vehicles and trailers — Test methods and
requirements”, published by the International Organization for Standardization
Standards Committee. It is based on ISO 4091 : 1 978

(ISO). It is expected that in due course ISO 4091 will be revised and aligned with
this British Standard. This standard includes requirements for vibration,
durability, and resistance to ingress of dust and water, and a reduced insertion
force between plug and socket. These do not appear in ISO 4091 at present.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
C omp liance with a British S tand ard d oe s no t of itse lf confe r immunity
from le gal ob ligatio ns.

S ummary of p age s

This document comprises a front cover, an inside front cover, pages i and ii,
pages 1 to 4, an inside back cover and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.

ii

© BSI 02- 2000

BS AU 1 94 : 1 984

c) 6 mV/A if the terminals in both plug and socket
are not readily accessible.
When tested as described
in , the insulation between the contacts and
between each contact and the case shall
withstand 1 000 V r.m.s. (50 Hz or 60 Hz)
for 1 min.

1 S cop e

This British Standard specifies requirements for
performance of electrical connections between
towing vehicles and trailers.
It applies to electrical connections type 24 N
and 24 S, used for vehicles fitted with electrical
equipment operating at a nominal voltage of 24 V,
and type 12 N and 12 S, used for vehicles fitted with
When tested as described in ,
electrical equipment operating at a nominal voltage
the
connector
shall
show no visible cracks or
of 12 V. These are specified in BS AU 197,
deformation
and
shall
not exceed the values

BS AU 198, BS AU 149a and BS AU 177a
specified
in
,
and
.
respectively.
When tested as
NOTE The titles of the publications referred to in this standard
are listed on the inside back cover.
described in , the increase in maximum voltage
drop shall be no higher than 50 % above the values
specified in .
When
When tested as described in
, the degree of
measured as described in , the insertion force
protection against ingress of dust shall be IP5X, as
shall be 150 N maximum. The withdrawal force
given in BS 5490. When tested as described
shall be 20 N to 150 N.
, the degree of protection against ingress of
When tested as in
water
shall
be the second characteristic numeral 4,
described in , each contact, but not more than
as
given
in

BS
5490.
two adjacent contacts simultaneously, one being the
When tested as
common return, shall be capable of
carrying 15 A d.c. continuously for 1 h, without the described in , there shall be no cracks in the
components and they shall not exceed the values
temperature of the contacts rising by more
specified in and by more than 50 %.
than 20 °C above the ambient temperature.
When tested as described in ,
When tested as described in ,
the connector shall not exceed the values specified
the maximum voltage drop shall be:
in and by more than 50 %.
a) 5 mV/A and 0.5 mV/A respectively, if all the
terminals are readily accessible;
b) 5.5 mV/A and 0.5 mV/A respectively, if the
terminals in either the plug or the socket are not
readily accessible;
2 . 4 C ontact insulation.
A. 4

2 . 5 Ab ility to withstand e xtre me

te mp e rature s.

2.1

A. 5

2.3

2.4

2 . 6 C orrosio n re sistance .
A. 6

2 Pe rformance

2.3

2 . 7 Re sistance to ingre ss of d ust and wate r.

2 . 1 Inse rtion and withdraw al force s.

A. 7 . 2

A. 1

A. 7. 3

2 . 2 C urre nt carrying cap acity.
A. 2

2 . 8 Vib ratio n re sistance .
A. 8

2.1

2 . 3 Voltage drop .

A. 3

2 . 9 D urab ility.

2.1

© BSI 02-2000

2.3

A. 9

2.3

1


BS AU 1 94 : 1 984

Ap p e ndix A

A. 4 Flash te st

Tests

The flash test shall be carried out on plug and socket
separately. The ambient temperature shall
be 23 ± 5 °C. The relative humidity shall

The insertion and withdrawal forces shall be
be 65 ± 5 %. Measure the insulation between the
measured between plug and socket of the same
contacts and between each contact and the case,
make. The ambient temperature shall be 23 ± 5 °C. when metallic, for capability to
The pins and tubes shall be dry and clean. Measure withstand 1 000 V r.m.s. (50 Hz or 60 Hz)
the insertion and withdrawal by a static test (dead for 1 min.
weight method) at the tenth cycle of insertion and
withdrawal. The cover shall be disengaged.
Subject the connector to the following temperature
cycle:
The ambient temperature shall be 23 ± 5 °C.
a) initial temperature of + 23 ± 5 °C;
Connections to the terminals shall be insulated
b) high temperature of + 70 ± 2 °C for 15 min;
cables of 1.5 mm2 cross section and 1 m minimum
c) low temperature of – 25 ± 3 °C for 15 min.
length. After the contacts have carried 15 A d.c.
continually for 1 h, measure the temperature of
After completion of the temperature cycle, subject
each contact at the terminals of both tube and pin, the connector to the tests described in ,
as close as possible to the insulation.
and .
A. 1 Me asure me nt of inse rtion and withd rawal

force s

A. 5 D e te rmination of ab ility to withstand
e xtre me te mp e rature s

A. 2 D e te rmination of curre nt carrying
cap acity

A. 1

A. 3

A. 4

A. 3 Vo ltage d rop te st

The voltage drop between the pins and the
corresponding tubes shall be measured between
plug and socket of the same make, at the tenth
insertion, according to either
,
or
as appropriate. The ambient temperature shall
be 23 ± 5 °C.
Provided that all terminals on the connector
are readily accessible, e.g. that connecting cables
are not moulded into either the socket or the plug,
measure the following voltage drops, with a current
of up to 10 A:
a) between the terminals of each pin and its
corresponding tube;
b) between each terminal and a point 10 mm from
the terminal on a connecting conductor
of 1.5 mm2 cross-sectional area.
If the terminals in either the plug or the

socket, but not both, are not readily accessible, e.g. if
a cable is moulded in, measure the following voltage
drops, with a current of up to 10 A:
a) between each accessible terminal, and a point
on the conductor connected to its corresponding
pin or tube 100 mm from the face of the plug or
socket;
b) between each accessible terminal and a
point 10 mm from the terminal on a connecting
conductor of 1.5 mm2 cross-sectional area.
If the terminals in both plug and socket are
not readily accessible, e.g. if cables are moulded in,
measure the voltage drops between each pair of
corresponding conductors at points on the
cables 100 mm from the faces of the plug and the
socket, with a current of up to 10 A.
A. 3 . 1

A. 3 . 2

A. 3 . 2

A. 3 . 3

A. 3 . 3

A. 3 . 4

A. 6 C orrosio n te st

This test shall be carried out in accordance with
BS 5466-1. The test time shall be 48 h. Carry out
the test on:
a) plug and socket mated and positioned as
mounted on the vehicle with cable side covered;
b) socket with cover closed and positioned as
mounted on the vehicle and with cable side
covered.
After having cleaned and dried the mated plug and
socket as specified in BS 5466-1, carry out the test
described in .
A. 3

A. 7 D e te rmination of re sistance to ingre ss o f
dust and wate r

. Carry out the tests described in
and
on:
a) a plug and socket mated;
b) a socket with the cover closed.
In each case, position the items as mounted on the
vehicle. The cable entry shall be fitted with a boot, if
it is normally provided with one, and a short length
of cable.
Carry out the
test as described in of BS 5490:1977.
A. 7. 1

A. 7 . 2

General

A. 7 . 3

A. 7. 2

Resis tance to ingress of dust.

7.5

A. 3 . 4

2

© BSI 02-2000


BS AU 1 94 : 1 984

A. 7 . 3

Resistance to ingress of water. Carry out the

Subj ect the components to sinusoidal vibrations in

test as described in BS 5490, but with the following

each of the three perpendicular planes for 1 6 h.

amendments.

Carry out the initial test along the central axis.

g

There shall be a constant acceleration of 5 . Change

a) The water pressure shall be increased
to 400 kN/m 2 (4 bar

1)

) approximately (see

8. 4

of

BS 5490: 1 977).
b) The radius of the oscillating tube shown

the frequency from 5 Hz to 50 Hz and 50 Hz to 5 Hz
during each 2 min. The change of frequency shall be
made progressively.

in Figure 4 of BS 5490: 1 977 may be increased,

A. 9 D urab ility te st

but it shall be provided with spray holes

The plug and socket, of the same make, shall

of 0. 8 mm diameter over the whole 1 80 ° of the

complete 1 000 cycles of insertions and

semicircle and shall be capable of delivering

withdrawals.

water at the rate of at least 1 0 L/min.
c) The specimen being tested shall be mounted on
a support with a vertical axis and located at
approximately the centre point of the semicircle
formed by the oscillating tube. It shall be sprayed
from every direction by oscillating the tube to the
limit in each direction at a rate of
approximately 90 °/s for 1 0 min.
A. 8 Vib ration te st

Mount the mated plug and socket on a fixture using
the designed fixing points, with the central axis
horizontal. Both the plug and socket shall include a
typical length of cable. The cables shall be positively
restrained to a separate fixture 1 m from the plug
and 300 mm from the socket.

1)

1 bar = 1 0 5 N/m 2 = 1 00 kPa.

© BSI 02- 2000

3


4

blank


BS AU 194:1984

Publications referred to
BS 5466,

Methods for corrosion testing of metallic coatings.

BS 5466- 1 ,
BS 5490,

Neutral salt spray test (NSS test).

Specification for classification of degrees of protection provided by enclosures.

Specification for electrical connections between towing vehicles and trailers with 6 V or 1 2 V
electrical equipment: type 12 N (normal).

BS AU 1 49a,

Specification for electrical connections between towing vehicles and trailers with 6 V or 1 2 V
electrical equipment: type 12 S (supplementary).

BS AU 1 77a,

BS AU 1 97, Specification for electrical connections between towing vehicles and trailers with 24 V electrical
equipment: type 24 N (normal).
BS AU 1 98, Specification for electrical connections between towing vehicles and trailers with 24 V electrical
equipment: type 24 S (supplementary).
ISO 4091 , Road vehicles — Electrical connections between towing vehicles and trailers — Test methods and
requirements 2 ) .

2)

Referred to in the foreword only.

© BSI 02 - 2 000


BS AU
194:1984

BSI — British Standards Institution
BS I is the indep endent national b ody res p ons ib le for p rep aring
Britis h S tandards . It p res ents the UK view on s tandards in E urop e and at the
international level. It is incorp orated b y Royal C harter.

Revisions

Britis h S tandards are up dated b y amendment or revis ion. Us ers of
Britis h S tandards should make s ure that they p oss es s the latest amendments or
editions .

It is the constant aim of BS I to imp rove the quality of our p roducts and services .
We would b e grateful if anyone finding an inaccuracy or amb iguity while us ing
this Britis h S tandard would inform the S ecretary of the technical committee
res p ons ib le, the identity of which can b e found on the inside front cover.
Tel: 02 0 89 96 90 00. Fax: 02 0 89 96 7 40 0 .

BS I offers memb ers an individual up dating s ervice called PLUS which ens ures
that s ub s crib ers automatically receive the lates t editions of s tandards .

Buying standards
O rders for all BS I, international and foreign s tandards p ub lications s hould b e
addres s ed to C us tomer S ervices. Tel: 0 2 0 899 6 9 00 1 . Fax: 0 2 0 899 6 7001 .

In res p ons e to orders for international standards , it is BS I p olicy to sup p ly the
BS I imp lementation of thos e that have b een p ub lis hed as Britis h S tandards,
unless otherwis e requested.

Information on standards
BS I p rovides a wide range of information on national, E urop ean and
international standards through its Lib rary and its Technical H elp to E xp orters
S ervice. Various BS I electronic information s ervices are also availab le which give
details on all its p roducts and s ervices . C ontact the Information C entre.
Tel: 02 0 89 96 71 1 1 . Fax: 02 0 89 96 7 048.

S ub s crib ing memb ers of BS I are kep t up to date with s tandards develop ments
and receive sub s tantial discounts on the p urchase p rice of s tandards. For details

of thes e and other b enefits contact Memb ership Adminis tration.
Tel: 02 0 89 96 70 02 . Fax: 02 0 89 96 7 00 1 .

Copyright
C op yright s ub s is ts in all BS I p ub lications . BS I als o holds the cop yright, in the
UK, of the p ub lications of the international s tandardization b odies . E xcep t as
p ermitted under the C op yright, D es igns and Patents Act 1 988 no extract may b e
rep roduced, s tored in a retrieval s ystem or transmitted in any form or b y any
means – electronic, p hotocop ying, recording or otherwis e – without p rior written
p ermis s ion from BS I.

This does not p reclude the free us e, in the cours e of imp lementing the standard,
of necess ary details such as s ymb ols, and size, typ e or grade designations. If thes e
details are to b e used for any other p urp os e than imp lementation then the p rior
written p ermiss ion of BS I must b e ob tained.

If p ermis sion is granted, the terms may include royalty p ayments or a licensing
agreement. D etails and advice can b e ob tained from the C op yright Manager.
BS I
3 89 C his wick H igh Road
London
W4 4AL

Tel: 02 0 89 96 70 7 0.