Re: replacing an illuminated switch

On Sat, 31 Dec 2005 16:54:56 +0000, Pooh Bear
<rabbitsfriendsandrelations@xxxxxxxxxxx> wrote:

>
>
>Steve Urbach wrote:
>
>> On 31 Dec 2005 06:52:51 -0800, "apa" <tacoma57@xxxxxxxxxxx> wrote:
>>
>> >Unfortunately the bulb works fine - the rest of the switch fell apart.
>> >I thought that maybe A) the AC with a dropping resistor would give me a
>> >60HZ pusing LED or that B) I could tap DC after the rectifier for the
>> >LED. Is it going to be enough trouble that I would be better off
>> >bagging the indicator light and putting in a plain old switch?
>>
>> Please pause for a moment and consider how close these (LED version)
>> connections bring your clean, filtered DC to your dirty, un-filtered
>> Mains.
>
>And why would that be a cause for concern ?
>
>Graham
Close(r) coupling of Mains EM disturbances into the DC.
Even the NEC requires a minimum spacing of Class 1 and Class 2
circuits in the same enclosure where a 'partition' is NOT provided.

Look at most 'good' Power supply designs. The Mains enter at one
point, are filtered, rectified...
The low voltage secondary never inter-mixes leads in this area. IMHO a
good design practice even if it were not 'suggested' by agencies like
UL, NFPA.
.

Relevant Pages

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  • Re: replacing an illuminated switch
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  • Re: replacing an illuminated switch
    ... >>Steve Urbach wrote: ... > Closecoupling of Mains EM disturbances into the DC. ... Simple proximinty won't do that. ... > Look at most 'good' Power supply designs. ...
    (rec.audio.pro)