Re: Whole house surge suppressors
From: w_tom (w_tom1_at_usa.net)
Date: 07/08/04
- Next message: w_tom: "Re: Whole house surge suppressors"
- Previous message: w_tom: "Re: Whole house surge suppressors"
- In reply to: Charles Perry: "Re: Whole house surge suppressors"
- Next in thread: w_tom: "Re: Whole house surge suppressors"
- Messages sorted by: [ date ] [ thread ]
Date: 7 Jul 2004 22:43:50 -0700
Communication ports are easily damaged if ports are used beyond their
design criteria. Two examples are RS-232 port to interconnect
buildings and stereos driving outside speakers. However, first one
must ask where was the incoming and outgoing path for that damage.
Does a surge enter on communication port, damage that port, then stop?
Of course not. First a complete circuit is established from cloud to
earth. After that circuit is conducting electricity through
everything in that circuit, only then does something fail. If that
circuit is incoming and outgoing via appliance - a condition where
1000+ volts means the 'whole house protector system was defective -
then the solution is not to supplement the protector. The solution is
to fix the 'whole house' protector and its so critically necessary
earth ground.
As noted previously, many communication ports, to communicate with
devices not adjacent to the computer, already have effective internal
protection. For example NIC (ethernet) port is typically good for in
excess of 1000 volts. That is effective protection that can be
overwhelmed if the necessary 'whole house' protector system is not
installed. Most critical component of that system? Single point
earth ground.
Do we fix the single point ground or do we install 'point of use'
protectors on every of well over 100 appliances inside the house?
Remember, GFCIs in kitchen and bathroom, furnace, electronic timer
switch, dishwasher, clock radio, portable phone, microwave, alarm
system - are but a few of the electronics that each need a $15 or $50
protector if the 'whole house' system is not properly installed.
Better and less expensive to fix the 'whole house' (secondary)
protection system.
Charles Perry cites a paper that is a 'must read' for anyone who
needs surge protection:
http://www.eeel.nist.gov/817/817g/spd-anthology/files/Enlightening.pdf
Same authors make same point in an applicaton note for builders and
other structural contractors - again must read:
http://www.pueblo.gsa.gov/cic_text/housing/surge/contractors.htm
In the Cozy Cabin example, simple principles of single point earth
ground are violated. Damage was made possible by human failure. The
Rambling Residence suffers from a similar failure. For example,
outside speakers are incoming wires that did not first connect to
single point ground before leaving the building. Where did that
transient enter or leave? The authors suspect induced electromagnetic
transient. However those wires easily could have been connected to a
direct surge by being buried, routed over conductive materials such as
concrete, or even in contact with another conductor - the tree. But
again, wires entered the building without first making contact to the
single point earth ground system. A blantant violation.
Other suspects could have contributed to the problem. Electrical
controls for the sprinkler system also complicate the installation of
a single point ground. Where or how did another structure - the
exterior pool - connect to building? Were building and pools
interconnected at a single point or did they too create ground loops?
Both pool and building should have been connected as if each were a
separate structure. If not, then the building could have ground loop
problems - no single point earth ground existed.
Earthing is the primary solution to surge protection which is also
why new homes should have Ufer or halo grounds. Grounding installed
bfore the foundation is even constructed. Purpose is to make earth
beneath equipotential - make the single point ground more effective.
Plug-in or 'point of use' protectors do not adaquately compensate for
a defective earthing system. Furthermore those plug-in protectors are
typically undersized and grossly overpriced - on the order of tens of
times more expensive per protected appliance.
That is the point of that nist.gov paper and so many other
industry professionals. Protectors are not the protection. Earthing
- the thing often forgotten because it is out of sight - is the most
important aspect of surge protection.
And we are only discussing secondary protection. What is the
primary protection? Examples of failures in a building's primary
protection system:
http://www.tvtower.com/fpl.html
Again, the less expensive and essential solution is earthing even in
the primary protector system.
"Charles Perry" <pipesandtobacco@hotmail.com> wrote in message news:<2l2bmtF7im90U1@uni-berlin.de>...
> The problem is not with the power supply, it is with the communications
> ports. Nine out of ten failed appliances that we examine have failures
> associated with the communications ports. If you don't provide the proper
> TVSS that ties the power and communications references together, then you
> will damage equipment.
>
> http://www.eeel.nist.gov/817/817g/spd-anthology/files/Enlightening.pdf
>
> A very good paper that mentions this.
>
> Charles Perry P.E.
- Next message: w_tom: "Re: Whole house surge suppressors"
- Previous message: w_tom: "Re: Whole house surge suppressors"
- In reply to: Charles Perry: "Re: Whole house surge suppressors"
- Next in thread: w_tom: "Re: Whole house surge suppressors"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
