terms of overall wiring safety, The National Electrical Code
(NEC) and the Institute of Electrical and Electronics
Engineers (IEEE) Standards are in general use throughout the
this regard, the NEC and the IEEE state that neutral to
ground connections are generally not permitted. THE NEC
States in Section 250-61 (b) Load Side Equipment "A
grounded circuit conductor shall not be used for grounding
non current-carrying metal parts of equipment on the load
side of the service. . ."
Suppressor Manufacturers who claim to obtain zero or no
voltage between neutral and ground using neutral to ground
bonding are out of compliance with the provisions, below of
The National Electrical Code and IEEE Standards.
major reason the grounded circuit conductor is not permitted
to be grounded on the load side of the service is that,
should the grounded service conductor become disconnected at
any point on the line side of the ground, the equipment
grounding conductor and all conductive parts connected to it
will carry the neutral current, raising the potential to
ground of exposed metal parts not normally intended to carry
current. This could result in arcing in concealed places and
could pose a severe shock hazard."
IEEE States in Section 184.108.40.206.1 Neutral to Ground Bond
". . .neutral-ground bonds are a common problem that
not only create shock hazards for operating personnel but
can also degrade the performance of sensitive electronic
some parts of Europe, Asia and the UK, ungrounded systems
remain a convention. Based on the long-standing tradition of
these ungrounded systems, it is obvious that such power
systems can be made viable. However, the United States has
followed a grounded approach, which is generally considered
safer and contributes to improved system performance.
Effect of Neutral to Ground Bonding on The Digital Office:
Networked Computers, Copiers, and Faxes.
Single point grounding is a concept that should be followed
in all networked, automated offices and computer
installations, from mainframe to PC. In many cases, single
point grounding already exists as the standard in most
construction wiring design. The purpose of single point
grounding is to prevent voltage differences from occurring
between pieces of equipment. With each unit referencing to a
single point of potential, no unwanted noise currents flow
between them. This is critical to the proper function of
interconnected / electrically connected, digital equipment.
Multiple grounding points cause ground loops. These paths
are a source of common mode noise that can cause a host of
computer problems such as data corruption, error codes,
printer and equipment lock-up.
effort to eliminate common mode noise, some TVSS
Manufacturers have developed TVSSs that bond neutral to
ground via a relay. Any TVSS that bonds neutral to ground,
will appear effective in eliminating of noise for the
protected equipment. However, it changes the ground
reference of the protected equipment in relation to any
connected equipment, (via LAN, Modem or data line) which
increases the potential for common mode noise, that cause
data corruption, error codes and lock-ups.
you test a TVSS for Neutral to Ground bonding.
GFCI (Ground Fault Circuit Interrupt) Test:
simple test to determine N-G bonding on a TVSS is the use of
a GFCI outlet. N-G bonded TVSSs will send additional current
back into the ground line, creating a ground fault. This
current will trip a ground fault interrupt, thereby making
it impossible to use an appliance or industrial grade GFCI
outlet with a N-G Bonded TVSS.
Plug a Suretest into the outlet receptacle of the suspect
TVSS and let it run through its startup diagnostic. It will
automatically show "FG" meaning "False"
or "Bootleg" Ground.
Earley, National Electrical Code Handbook,
Seventh Edition, National Fire Protection Association,
Quincy MA, 1996
Morrison / Lewis Grounding
and Shielding in Facilities John Wiley & Sons, Inc. New York, NY, 1990
M. Waller, PC
Power Protection Howard W. Sams & Company, Indianapolis, IN, 1989
M. Waller, Computer
Electrical Power Requirements Howard W. Sams & Company, Indianapolis, IN, 1987
Recommended Practice for Powering and Grounding Sensitive
The Emerald Book, IEEE Std.