In message
<7d25799235e00f4c9b04eca410c1c5bf8f0ba...@szxema502-mbx.china.huawei.com>
, dated Wed, 11 Sep 2013, "Zhangguoqing (A)" <zhangguoq...@huawei.com>
writes:
6.3 Protection of the telecommunication wiring system from overheating
Equipment intended to provide power over the telecommunication wiring
system to remote equipment shall limit the output current to a value
that does not cause damage to the telecommunication wiring system, due
to overheating, under any external load condition. The maximum
continuous current from equipment shall not exceed a current limit that
is suitable for the minimum wire gauge specified in the equipment
installation instructions. The current limit is 1,3 A if such wiring is
not specified. NOTE 2 The minimum wire diameter normally used in
telecommunication wiring is 0,4 mm, for which the maximum continuous
current for a multipair cable is 1,3 A.
1.4.11 Power from a telecommunication network
For the purpose of this standard, the power available from a
TELECOMMUNICATION NETWORK is considered to be limited to 15 VA.
My question is , if a equipment intends to provide power over the
telecommunication wiring system, the current and the power should be
controlled at the same time? or, only the current should be controlled?
1.4.11 is not a requirement, it is an assumption. Why it is stated, and
why it is included under General conditions for tests are questions that
the authors of the text should address.
Unless a 'creative' interpretation of 1.4.11 indicates otherwise, I
suggest that 1.4.11 has no effect on 6.3 and you need to limit only the
current.
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
If dictionaries were correct, we would only need one, because they would all
give the same information.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
-
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