From: "Barry Singleton" <[email protected]> Subject: Re: BS EN 41003: 1997 now available?
I do not agree that the NB should decide. Safety requirements can be met by self declaration. to the applicable standard(s). Best regards Barry Singleton Approvals Specialist email:[email protected] Securicor 3net Limited Ringway House Bell Road Daneshill Basingstoke Hants RG24 8FB UK Tel: 44 (0)1256 792174 Fax: 44 (0)1256 840429 ------------- Original Text From: "Ian Chapman" <[email protected]>, on 11/02/97 13:39: To: <[email protected]> A Notified body should figure out what is required and what is not required not your boss. Under the TTE directive TTE equipment must be approved by a Notified Body to be marketed in the EU, if I understand the rules that is. If you were unable to find a Notified Body to agree with your safety assessment you would have a delay in your product. Regards Ian. In message " BS EN 41003: 1997 now available" sent on Feb11, [email protected] writes: >Jon D Curtis wrote: > >> 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. > >Gee, I hate to disagree with you Jon. > >I'm not supporting the argument I'm presenting. It was used >by a former boss to a great extent. More like a little >knowledge is a bad thing, especially when marketing gets a >hold of something like this. It was a battle. > >The ring signal of which you speak is in what I've known >as the 'local loop' between [I believe] a Class 5 office >[last in line before the subscriber] and the subscriber on >the analog line. The ring signal is handled *sometimes* >[because I'm not 100% sure] by a *channel bank*. There are >analog and digital channel banks. Some that I'm familiar >with control the interface between the T1 line and the >ring voltages out to the subscriber. A T1 line by spec >cannot handle the ring voltage. > >Now, if your product is a T1 IMUX device or a DCS device >*behind* a channel bank, that is to say not on the >subscriber side of the channel bank, the IMUX or DCS device >handles only 48vdc power [and sometimes 24vdc] and the >T1 signal levels. > >Now for Europe, substitute the above use of T1 with E1, >remove the Bell term "Class 5 office", and the scenerio >is very much the same. I would appreciate any corrections >here. > >So the voltages handled by this E1 device are: > > a power supply of 48vdc and > > the signals as defined in G.703 > >There are no voltages anywhere near the 75vdc lower >limit of the LVD as defined in 73/23/EEC, Article 1. > >So, the conclusion could be any telco device powered >by 48vdc and only handling E1 signalling is NOT >covered by the LVD - 73/23/EEC. > >This same argument was used by my former boss to try >circumventing UL testing, i.e. 48vdc being in the SELV >and NOT a hazzard. > >I got him nailed on both T1 and E1 devices by pointing >out that safety testing of a device is not solely dependent >upon normal use voltages. It is used to test the device >for overcurrent overtemp overvoltage abnormals, ground >currents ... conditions for safe operation attested by an >independent third party. > >Comments. > >************************************************************ >------------------------------------------------------------ > The comments and opinions stated herein are mine alone, > and do not reflect those of my employer. >------------------------------------------------------------ >************************************************************ >
