Vintage Products

Re: Is you'r old b&o earthed !!!

tomsloat — Tue, 17 Mar 2009 15:43:14 GMT

geearr:

Hi Tom

I have just had my BM2200 open once again and note that it is fitted with a three core cable. The earth lead goes to a common point on the steel base plate. Not sure whether this is the original cable but it does have a properly moulded plug. Like you, I feel better when these machines are fitted with a proper earth lead but have noted that a large number of B&O units only have the two leads. There must be a logical reason for all of this but I don't know it.

Regards

Geoff

thanks geoff if yours is earthed i think i'll do mine

Re: Is you'r old b&o earthed !!!

tournedos — Tue, 24 Feb 2009 04:52:32 GMT

The added protective earth wire will not bring you more protection unless the unit is connected to a grounded socket. Sometimes it can actually make things worse, i.e if you have a grounded extension cord fitted to a non-grounded socket. When one of the grounded units in that extension gets a fault, the live mains may be conducted to casings of all the other grounded units via the protective earth.

In the old times (but not all the way to the valve radios), the equipment usually had a wooden case and the mains was limited to the primary of the transformer and the power switch. These are quite safe without PE as long as all insulation is intact and all wires stay connected (especially the mains switch area is a bit scary in some models, I always add some shrink tube and tie wraps when I'm in there to keep the wires safely at hold even if the mains switch disintegrates).

The electrical regulations vary wildly from country to country, and did even more before EU harmonization efforts. Still in the 70s, here in Finland the regulations only mandated earthed mains sockets in rooms that had some kind of an exposed earth, like kitchen sinks and water taps. In those days, equipment that wasn't safe to use in those environments had a "class 0" plug that would not fit into an earthed socket (until some experimental person used a knife on it...). Those that were double insulated, i.e externally safe even during a fault, have a flat plug that fits into both kinds of sockets, and most modern AV equipment falls into this category.

Re: Is you'r old b&o earthed !!!

Medogsfat — Tue, 24 Feb 2009 02:39:58 GMT

Not just B&O, loads of electrical appliances are fitted with 2 core cable & no earth.

Chris.

Re: Is you'r old b&o earthed !!!

geearr — Tue, 24 Feb 2009 01:59:14 GMT

Hi Tom

I have just had my BM2200 open once again and note that it is fitted with a three core cable. The earth lead goes to a common point on the steel base plate. Not sure whether this is the original cable but it does have a properly moulded plug. Like you, I feel better when these machines are fitted with a proper earth lead but have noted that a large number of B&O units only have the two leads. There must be a logical reason for all of this but I don't know it.

Regards

Geoff

Re: Is you'r old b&o earthed !!!

tomsloat — Wed, 18 Feb 2009 17:05:55 GMT

Thanks peter

had me worried i'm a lift engineer and we have to earth everything thats remotely conductive ..oh well if they are all like it i suppose it's nothing to worry about

tom

Re: Is you'r old b&o earthed !!!

Peter — Wed, 18 Feb 2009 16:58:27 GMT

Totally standard - don't worry about it!

Is you'r old b&o earthed !!!

tomsloat — Wed, 18 Feb 2009 15:46:39 GMT

Hi was just wondering if this is nessesary.

i've just noticed that despite an almost totaly metal case the mains cable on my bm2200 is only a twin and has no earth connection.

i am thinking of earthing it but i can find no reference to an earth in the drawings ?????

help appricated

thanks tom