(Surge
Protector Questions?)
BRICK WALL SURGE PROTECTORS WILL
NOT Divert
Surge Current to Ground
Almost all manufacturers
of shunt mode surge protectors (those utilizing MOV’s) design their products
to divert surge current equally between the ground and neutral
wires. A surge protector should not divert surge current to
the ground wire.
DATA LINE
PROTECTION?
Our sales staff repeatedly hears
this same story: It seems a company has experienced
considerable surge damage to electronic equipment. The shunt
mode surge protectors would appear to have done their
job by protecting the loads from the front end (power line).
The damage, in their estimation, resulted from surge current
that traveled down the data lines. How do they know this? All
the damage appears to have originated at the data ports, hence
they conclude that the surge must have traveled this route.
Their solution: They need data line
surge protectors. |
 |
They are right in as much as the
damaging current did propagate through the data lines. However,
damaging surges do not originate in dataline circuits.
Their systems do not need data line
surge protectors. Interconnected systems need powerline surge
protectors that do not divert surge current to the ground
wire.
INTERCONNECTED SYSTEMS
AND GROUND LOOP CONTAMINATION
Interconnected (networked) systems, so
prevalent in today’s commercial/industrial world, have made shunt
mode technology used in most surge protectors (origins 1972) inappropriate. Equipment sharing
common power and data lines form circuits between themselves via the
ground wire (both referenced at the load). What does current do in a
closed circuit? It flows. A powerline surge diverted to the ground
wire by a shunt mode surge protector will make its way to the chassis, through the motherboard
(which is also grounded at the chassis), onto and through the data
lines (which use the powerline ground as a voltage reference and are
also connected at the motherboard) and to the data ports of the rest
of the connected system. This is how most data line surges
originate.
DATA LINE
NOISE
Smaller surges diverted to ground wires
by a shunt mode surge protector may not immediately damage equipment (though the cumulative effect
can eventually cause failures). On the other hand, low level surge
current diverted to the data lines by a shunt mode surge protector (via the ground wire) can
immediately scramble data, slow down data transfer and cause mis-operations or lock-ups as a consequence of its effect as system
noise (unwanted current on the data lines).
BRICK WALL SURGE
PROTECTOR SERIES MODE
TECHNOLOGY
| Brick Wall surge protector products are based on the current (hence
voltage) limiting of a massive inductor. Residual energy that
leaks through is captured by a series of electrolytic
capacitors. There it is slowly leaked back to the neutral at a
harmless level. Outside of trivial amounts of parasitic
capacitance our Series Mode surge protectors do not put any surge
current on the ground of your systems. Engineers of an MOV
based surge protector face the dilemma of what to do with
potentially large amounts of surge current. They don’t want to
overload the neutral and want to prolong the life of the MOV.
Using two MOV's and diverting equally between the
ground and neutral wire prolongs MOV life and prevents
overcurrent on the neutral. Series Mode surge protector technology presents no
such dilemma. |
 |
BRICK WALL SURGE PROTECTORS WILL
NOT Divert
Surge Current to Ground
| 
