Scott, you do not have to test for power line harmonics or flicker if  1)
your product is not mains powered, and 2) you have no intention of selling
it along with a particular power source, and 3) you do not specify that it
be used with a particular power source. If the choice of power source is up
to the system manufacturer, he is responsible for compliance of the system
including all of its variants.
Richard Woods 
Sensormatic Electronics 
Tyco International 

-----Original Message-----
From: Scott Douglas [mailto:[email protected]]
Sent: Tuesday, October 22, 2002 8:02 AM
To: [email protected]
Subject: Do I need to Test for Harmonics?


Fellow Listees:

There were some recent threads regarding what testing is required for a
product that obtains power from a supply external to the product and maybe
not supplied by the manufacturer. I think the questions were related to EFT
or surge.

I have a similar situation. Our products are network powered; that is, there
is a ferroresonant power supply connected to the network and we just tap
into that available power. This is CATV land and not Telco. We do not make
the supply nor do we sell them. Our products have switching supplies which
run on the quasi-square wave provided by the ferroresonant supply. Voltage
of the supply is in the 60-90 VAC range.

Question is: EN 50083-2 : 2001 (4.1.2 Disturbance Voltages From
Equipment...) says that if our products fall within the input current range
of EN 61000-3-2, then the tests and limits of that standard apply. Then EN
61000-3-2 : 2000 (1. Scope) says that the standard applies to products
intended to be connected to public low-voltage distribution systems.

One argument says that we are not connected to the public low-voltage
distribution system, instead the ferroresonant supply is. Therefore, since
we ARE NOT "connected" we do not need to do the harmonics test. The flip
side argument says that we still have to test harmonics because the supply
does nothing but provide power to our product and therefore we ARE
"connected".

Understand that this "system" consists of power supplies and amplifiers,
etc. from one or more than one supplier (read that more than one
manufacturer). We cannot guarantee we are the sole provider here, in fact
will most likely not be the sole provider. Especially since we do not
manufacture or sell power supplies.

So all powerful and wise list, what's a mother to do? Do I, or do I not,
test? Am I required to test? Have I missed something?

Thanks for all of the wisdom you are about to impart.

Regards,
Scott Douglas
Senior Compliance Engineer
Narad Networks
515 Groton Road 
Westford, MA 01886
phone: 978 589-1869
[email protected]
www.naradnetworks.com <http://www.naradnetworks.com/> 
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