Hi Alexandru:
> 1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent
to
> Reinforced Insulation?
No.
The scheme of protection against electric shock relies on
passive devices, not active devices.
As a general rule, active devices, e.g., transorb, are not
allowed as equivalent to one element of a two-safeguard
scheme, i.e., basic insulation and supplementary insulation.
For example, a GFCI/RCCB/ELCB could not be used as a
substitute for supplementary insulation because it is an
active device.
Active schemes are permitted where additional enviromental
conditions may exist that could bypass either or both Basic
Insulation and Supplementary Insulation (or Reinforced
Insulation). For example, GFCI/RCCB/ELCB is required for
environments might be wet, where that wetness could bypass
the insulation.
Another general rule is that deliberate operation of a fuse
is not permitted. (I do not have the rationale for this
rule.)
(Your characterization of "Basic Insulation + Fuse & Transorb"
as equivalent to "Reinforced Insulation" is incorrect.
Reinforced Insulation is defined as a single, robust insulation
equivalent to Double Insulation. The fact that your scheme
includes Basic Insulation as an element means that the system
cannot be Reinforced Insulation. A better characterization
would be equivalent to Double Insulation.)
> 2. Does the transorb have to comply with a specific EN safety standard
(like
> one applicable to Y caps)?
Yes, if one exists.
In the situation you describe, the transorb must be able to
dissipate the full mains voltage and current, where the
current is the circuit prospective current, for the maximum
duration of the fuse, and still be operative for the next
such event.
Additionally, the transorb would need to dissipate the mains
current at a current just below the fuse operating point, and
do so indefinitely.
And, there would be additional requirements.
Best regards,
Rich
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Ron Pickard: emc-p...@hypercom.com
Dave Heald: davehe...@attbi.com
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
Jim Bacher: j.bac...@ieee.org
Archive is being moved, we will announce when it is back on-line.
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
