From: =?iso-8859-1?Q?Juan_Pedro_Pe=F1a?= <[email protected]>

Doug:
At least in Spain, public switching telephonic network works with 48 V =
dc but the ringing signal could reach 75 V ac (hazardous voltage =
according to LVD). In fact, if you catch both poles of a telephone line =
during the ringing process, you will suffer that voltage. So for that =
reason, LVD applies.

----------
De:             Doug McKean[SMTP:[email protected]]
Enviado:        lunes 10 de febrero de 1997 21:05
Para:           Juan Pedro Pe=F1a
Cc:     [email protected]; [email protected]
Asunto:         Re: BS EN 41003: 1997 now available

I'll throw in two cents worth.=20

We have been having a discussion concerning where standards=20
do and do not fit in to particular pieces of equipment.=20

I have had discussions in the past with people about=20
48VDC TTE products and the LV Directive - 73/23/EEC. =20

The LVD specifically states in Article 1=20

"For purposes of this Directive 'electrical equipment' means=20
 any equipment designed for use with a voltage rating of=20
 between 50 and 1000V for alternating current and between=20
 75 and 1500V for direct current, other htan the equipment=20
 and phenomena listed in Annex II."=20

Annex II goes on to list=20

"EQUIPMENT AND PHENOMENA OUTSIDE THE SCOPE OF THE DIRECTIVE

 Electrical equipment for use in an explosive atmosphere=20
 Electrical equipment for radiology and medical purposes=20
 Electrical parts for goods and passenger lifts
 Electricity meters
 Plugs and socket outlets for domestic use=20
 Electric fence controllers=20
 Radio-electrical interference"

Now, even when TTEs operating at 48vdc allow for a=20
Bellcore lower/nom/upper limit of 42.4/48/56.5 tolerance,=20
those dc TTEs are not covered by the lower=20
75vdc limit of the LVD.=20

So that 115/230 VAC TTEs were included, but=20
the 48VDC versions of the same model weren't.

Comments?=20

I'd really like to know how wrong I am.  This was the basis=20
of one of those really terrible debates I had with a former boss=20
where I wrote him up in a memo to his boss.=20


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