The National Electrical Code (NEC),
ANSI/NFPA 70 considers information technology equipment (ITE)
installed in ITE rooms—more commonly called computer rooms—as
special equipment. As described in Section 90-3, chapters 1
through 4 serve as the base requirements for special equipment
except as further amended by chapters 5 through 7. For
computer rooms and the ITE located within them, the
requirements in chapters 1 through 4 are specifically modified
by Article 645, Information Technology Equipment. In fact, the
Scope [645-1] of Article 645 not only covers ITE located in
computer rooms, but also covers power-supply wiring, equipment
interconnect wiring and grounding of ITE in the same room, all
of which will be discussed in this article.
Computer room constructions vary, but
common features of most are self-contained HVAC systems,
fire/smoke monitoring systems, automatic sprinkler or gaseous
agent fire extinguishing systems, fire-rated walls, raised
floors, under-floor wiring systems, and emergency power-off
systems. Also, because of the critical nature of the 24 hr/7
day operation of most computer rooms, access typically is
restricted to authorized personnel.
The intent of Article 645 is to allow for
modification and, in some cases, relaxation of the general
electrical wiring methods required by chapters 1 through 4 of
the Code for special equipment installed in computer
rooms, but only if the room complies with all the requirements
in Article 645. In fact, Section 645-2 establishes special
design conditions and use restrictions that a computer room
must comply with in order for the use of Article 645 to be
permitted. These conditions include:
• provision of power disconnect means
in the room [645-2(a)];
• provision of separate
heating/ventilating/air-conditioning (HVAC) system
[645-2(b)];
• use of listed ITE [645-2(c)];
• occupancy limited to trained
personnel [645-2(d)];
• separation of the room from other
occupancies by fire-resistant-rated walls, floors, ceilings
and protected openings [645-2(e)]; and
• construction of the room per the
applicable local building code [645-2(f)].
Computer room constructions that do not
meet the six conditions of Section 645-2 are required to
comply with chapters 1–4 without modification.
[NEC Code Making Panel 12 (CMP-12),
the CMP responsible for maintenance of Article 645, is
considering a revision in the 2002 NEC to remove the
condition [645-2(f)] requiring compliance of the computer room
with the applicable building code since this condition,
although valid, is non-electrical in nature.]
While the NEC is the installation
code covering practical safeguarding of persons and property
from hazards associated with electricity, the NFPA occupancy
standard that often, but not always, is adopted by local
jurisdictions as a companion set of requirements is the
Standard for the Protection of Electronic Computer/Data
Processing Equipment, NFPA 75. NFPA 75 establishes minimum
requirements for the protection of computer rooms and areas
from damage by fire or its associated effects, and considers
such risk factors as threat of fire to occupants and property,
life safety aspects of computer room function, and economic
loss of equipment, function and records. An awareness of NFPA
75 is important for persons applying Article 645 because the
Article 645 is extracted into NFPA 75 and NFPA 75 is mentioned
prominently in the fine print notes (FPN) of Article 645.
Photo
1. Dedicated HVAC in ceiling above information technology
equipment, along with smoke detector.
ITE Listing
Requirements
Information technology equipment produced
today generally is listed to either ANSI/UL 60950, Standard
for Safety of Information Technology Equipment, or one of its
predecessors, UL 1950 or UL 478. As part of the international
and U.S./Canadian harmonization efforts, UL 1950 and UL 478
are being phased out in the U.S. and by 2005 will be replaced
entirely by UL 60950. ANSI/UL 60950 is based on IEC 60950, the
international standard for Safety of Information Technology
Equipment, and is also harmonized with the Canadian Standards
Association’s standard of the same name, CSA C22.2 No.
60950.
Manufacturers of ITE listed by UL are
identified in UL’s Electrical Appliance and Utilization
Equipment (Orange) Directory, typically in the product
category for Information Technology Equipment Including
Electrical Business Equipment (NWGQ). The General, or Guide
Information [see sidebar] for this category describes the
generic types of ITE listed to UL 60950. More importantly, it
also describes special considerations associated with the
installation and use of ITE. UL develops this guide
information with authorities having jurisdiction (AHJs) in
mind so that AHJs are able to efficiently determine any
general installation considerations for listed ITE. This same
information can also be found in UL’s General Information
for Electrical Equipment (White) Directory, and in electronic
format at Underwriters Laboratories’ website: http://www.ul.com/database/index.htm.
UL 60950 includes numerous requirements
that originate from, or allow for installation of ITE in
computer rooms in accordance with Article 645. These
requirements can be grouped into several areas.
Supply Connections
For power supply connections to the branch
circuit (designated the "a.c. mains supply" in IEC
terminology), the wiring method associated with listed ITE
typically will be either cord connection or field (fixed)
wiring.
For cord connections, a common construction
is listed flexible cord, typically Type SJ or SO, with a
listed attachment plug assembled on one end and a strain
relief bushing and internal terminations on the other end.
By nature of Section 5-2.2 of NFPA 75,
power supply cords of listed ITE intended for use in computer
rooms are limited to a maximum of 15 ft. (4.57 m) in length.
This power supply cord length restriction is intended to
encourage placement of under-floor receptacles near the
equipment, allow for efficient interchange, and help prevent
damage to the cord after installation.
For field-wired (fixed) connections, UL
60950 requires a wiring compartment that allows for proper
connection in the field of the equipment to the a.c. mains
(supply). The wiring terminals and location in the equipment
are required to allow for inspection by an AHJ for proper
connection in accordance with chapters 1-4 of the Code.
Since most ITE installed in computer rooms
are continuous loads on the branch circuit, UL 60950 requires
that conductors and power supply cords associated with the
supply connection be rated no less than 125 percent of the
marked rating of the ITE [645-5(a)]. For example, ITE with a
power supply cord having an attachment plug with a 30 ampere
configuration (e.g., NEMA L5-30) is required to have a marked
electrical current rating for the ITE of no more than 24
amperes.
Interconnect
Cables
Inside computer rooms interconnect cables
usually are listed cable types (e.g., CL2, OFC, etc.).
However, those cables actually shipped with the listed ITE may
not necessarily be individually listed. Cables that are not
listed generally are limited to 10 ft (3.05 m) or less in
length and are individually evaluated as part of the listing
investigation. In fact, they are considered part of the listed
ITE. Although these cables may not be individually listed,
they are required to meet minimum construction, performance
and marking requirements specified in UL 60950.
For example, if an interconnect cable
supplied with the ITE is not individually listed, the
interconnect cable is restricted in length and, unless part of
a limited power circuit, is required to be jacketed.
Additionally, the cables are subjected to UL VW-1 flammability
requirements and are required to have a marking or tag
associating the cable with the listed ITE.
Cables not supplied with the listed ITE and
that are selected at the time of installation of the equipment
in the computer room are required to be individually approved
by the AHJ at the time of installation. Most cables are added
at the time of installation due to the wide variety of room
sizes and configurations associated with computer rooms.
Photo
2. LAN cables, CAT-5, and inter-connecting cables to rack
mounted equipment.
Article 645 is structured so that
interconnect cabling requirements are separated into above-
[645-5(c)] and under-floor [645-5(d)] applications.
For above-floor applications any listed
cable can be used if protected against physical damage and
used per its NEC restrictions and listing. For example,
listed Class 2 wiring that is routed above the floor is
permitted for Class 2 applications if the circuits and
installation are in accordance with Part C of Article 725.
However, it is more common for interconnect
cables in computer rooms to be located under the raised floor.
This type of installation allows for more flexibility routing
the cables and for easier relocation of ITE within the
computer room when needed. It also reduces potential trip
hazards to personnel working in the computer room.
Unfortunately, one implication of cables being permitted to be
installed under raised floor is that unused cables tend to
accumulate, in particular when formal cable management
programs are not in place that require removal of cabling
which is no longer being used. Accumulated cables become a
concern due to increased fire load, reduced airflow and
potentially impacted fire suppression.
For the year 2002 NEC, CMP 12 is
considering whether to add a new requirement to 645-5(d) to
specifically prohibit abandoned cables from being allowed to
accumulate in underfloor areas of computer rooms. Any action
will be correlated with CMP 16's consideration of a similar
requirement in Article 725.
All power cables, communication cables,
connecting cables and interconnecting cables are permitted
under the floor provided that (a) the raised floor is a
suitable construction and the area under the floor is
accessible [645-5(d)(1)], (b) ventilation in the under-floor
area is used for the computer room only [645-5(d)(3)], and (c)
any openings between the under- and above-floor areas protect
any cables routed through the opening against abrasion and
minimize the entrance of debris [645-5(d)(4)].
Under the floor cables not associated with
the branch circuit are required by Section 645-5(d)(5)(a) to
be in a raceway, unless they are
• a cable specified in 645-5(d)(5)(c),
such as listed Type CL2, PLTC, or CM, and used per the
referenced article (e.g., Class 2 per Article 725); or
• listed type DP cable having adequate
fire-resistant properties as described in 645-5(d)(5).
Type DP cable was introduced into Article
645 in 1996 and is permitted for both above- and under-floor
wiring applications in computer rooms. Type DP cable is a
jacketed cable, designated as either type DP-1, DP-2 or DP-3,
and is listed by UL under the product category for
Data-Processing Cables (EMRB). All DP cables comply with the
UL 1581 vertical tray flame tests referenced in the FPN to
645-5(d)(5).
Typically, Type DP-1 and -2 cables are used
for a.c. power applications, whereas Type DP-3 is used for
data transfer and other low voltage applications. DP-1 cable
is rated 600 volts in conductor sizes 18 to 4/0 AWG copper or
12 to 4/0 AWG aluminum. DP-2 cable is rated 300 volts in
conductor sizes 24 to 8 AWG copper or aluminum. The most
common type, Type DP-3 cable, is provided in conductor sizes
30 to 10 AWG, but is restricted for use in circuits having a
maximum available voltage of 30 volts rms/ 60 V d.c. that also
meet the power limits associated with limited power circuits
mentioned in Section 725-41(a). (See below for further
discussion of limited power circuits.)
Although neither Section 300-22(d), Article
645 nor NFPA 75 designate the under-floor area of a computer
room a plenum, use of plenum (P), riser (R), or general
purpose (G) rated cable is permitted to be used in under-floor
areas [645-5(d)(5)(c)]. These cables are identified by the P,
R and G suffixes marked on the jacket of the listed cable.
Also, although the NEC does not
designate the under-floor area of a computer room a plenum,
some building codes designate this area as a plenum. For
computer rooms impacted by these codes, the plenum
classification sometimes will be waived by local AHJs if the
computer room incorporates additional constructional features
such that in the event of a fire all air circulation stops.
[For the year 2002, NEC CMP 12 is
considering a proposal to revise 645-5(d) to require that all
air circulation stop in a computer room if a fire is detected.
Also, there has been some debate in the field whether the NEC allows for power supply cords originating from ITE above the
floor to be routed below the raised floor to receptacles
mounted underneath (e.g., server plugged into under-floor
receptacle). CMP 12 is also considering a proposal to revise
Section 645-5 to clarify this issue.]
Photo
3. Raised floor for access to interconnecting cables and
ease of reconfiguring systems.
Grounding
As required by Section 645-15, UL 60950
requires mains-connected ITE to be either grounded
(protectively earthed in IEC terminology) or double-insulated
(Class II in IEC terminology—not NEC Class 2!). In
practice most ITE found in computer rooms is grounded and is
not double insulated.
Generally, the equipment grounding
requirements for ITE intended for use in computer rooms are no
different than the grounding requirements for other ITE. More
specifically, for:
• equipment that is permanently
connected to the supply, a terminal for equipment grounding
is required, and the terminal intended for connection of the
equipment grounding conductor is identified in accordance
with Section 250-126. Although use of a green color terminal
remains common, more commonly used is the IEC symbol for
protective earthing (grounding), often described as an
inverted Christmas tree in a circle (IEC 60417 Symbol No.
5019: );
• cord/cable connections,
identification of the grounding conductor is usually
accomplished by use of a conductor with an insulation
covering that is either green, or green with one or more
yellow stripes. The internal termination of the grounding
conductor inside the ITE is usually marked with the same IEC
grounding symbol described above.
There is one type of ITE unique to computer
rooms and that has special grounding considerations—the
stand-alone power distribution unit (PDU), often called a
computer power center. PDUs are listed as ITE to UL 60950 and
typically distribute power to one or more pieces of ITE in the
computer room. Usually, they have a
• computer-style cabinet;
• cord/cable connection to a branch
circuit supplied through a floor-mounted receptacle;
• a large internal isolation
transformer and grounding system to improve safety and limit
electrical emissions; and
• overcurrent protection for output
wiring in the form of circuit breakers or supplementary
protectors.
This type of equipment is noteworthy from a
grounding/bonding perspective because Section 645-15 does not
consider the secondary of the PDU’s isolation transformer a
separately derived source for the purposes of applying Section
250-20(d). This provision is allowed because the function of
stand-alone PDUs is basically the same as the function of the
same construction that used to be, and sometimes is still,
integral to the ITE. For PDUs, the isolation transformer,
grounding, and distribution wiring simply have been removed
from inside the ITE/computer and redesigned into a stand-alone
ITE cabinet. This design allows for additional flexibility
with the moving and configuring of ITE in the computer room
As part of their listing, listed PDUs are
subjected to the same construction and performance
requirements as other ITE evaluated to UL 60950. However,
their isolation transformers and derived secondary circuits
internal to the PDU are subjected to additional Article
250-based grounding requirements that have been adapted to be
compatible with ITE.
Photo
4. Typical UPS system and bypass switch. This UPS unit is
not fixed in place.
Equipment
Disconnect
Section 645-11 requires uninterruptible
power supply (UPS) systems with the capability of supplying
more than 750 volt-amperes to have a disconnect means that
disconnects all power to electronic equipment in the computer
room in the event of an emergency. This requirement applies
both to the equipment’s input and output circuits, and to
any large capacity batteries associated with the equipment.
The disconnect for such equipment is
required to allow for installation in accordance with Section
645-10. When activated, it must disconnect power to all
electronic equipment and the dedicated HVAC system, and
trigger fire/smoke dampers to close. The basic intent of this
disconnect requirement is to provide for disconnection of all
power sources in a computer room in the event of a fire so
that fire fighting personnel may extinguish any fire with all
electrical equipment de-energized.
Stand-alone UPS equipment are listed to
ANSI/UL 1778, the Standard for Safety of Uninterruptible Power
Sources. The UL product category associated with ANSI/UL 1778
is Uninterruptible Power Supply Equipment (YEDU). ANSI/UL 1778
also includes requirements based on Article 645 for any UPS
that the manufacturer specifies is suitable for installation
in a computer room.
Since some ITE also have internal battery
power sources capable of supplying more than 750 volt-amperes,
UL 60950 also includes requirements to address the Article 645
disconnect requirement. For battery circuits in individual ITE,
an integral disconnect is required for all internal battery
circuits capable of supplying more than 750 VA. However, UL
60950 allows for orderly shutdown of internal ITE circuits by
permitting a five-minute period before full disconnect is
required of all batteries inside the ITE.
To allow for connection of the ITE to the
computer room’s disconnect system required by Section
645-10, ITE typically will be provided with either terminals
or a connector for this connection. This interconnection from
the equipment to the computer room disconnect at the computer
room entrance may allow for field configuration because
sometimes the ITE is installed in computer rooms established
in accordance with Article 685, Integrated Electrical Systems,
as is permitted by the Exception to Section 645-11. Article
685 does not require individual equipment to have an
independent disconnect function if an orderly shutdown of a
complete system of interconnected equipment is required to
ensure safe operation of entire integrated electrical system
(e.g., computer room in a chemical processing plant).
For the year 2002 NEC, CMP 12 has received
several proposals and comments basically proposing that all
disconnect requirements be removed from Article 645. The
rationale was based largely on concern that false activation
of disconnect switches could result in large economic hardship
on businesses (e.g., banks) that rely on data processing
centers/computer rooms. The CMP was to consider these
proposals in depth at the December 2000 ROC meetings.
Photo
5. Typical fire alarm control panel monitor (FACP) for
fire suppression system in information technology room.
Photo
6. UPS By-Pass transfer switch for UPS system for ITE
room.
Markings
Nameplate. Listed ITE is required by UL
60950 to have a nameplate marking that includes manufacturer’s
name, voltage, frequency and maximum rated loads in amperes.
This marking is compatible with the marking requirements of
Section 645-16. The nameplate marking also includes the
listing mark and typically is provided in a readily visible
location on the outside surface of the equipment. However,
this marking also is permitted to be in an operator accessible
area if it is easily accessible after the equipment is
installed.
Class 2/Limited Power Circuits. Input
wiring terminals intended to be connected to, and powered by NEC Class 2 circuits are marked "Class 2," as described
in Sections 725-2, 725-41 and Tables 11(a) and 11(b).
Similarly, output circuits/circuits supplying Class 2 power
from the ITE are marked "Class 2."
Additionally, all other output circuits and
connectors are limited power circuits supplied by UL 60950
Limited Power Sources, unless (a) they are clearly
telecommunication circuits (e.g., RJ-11 telephone jack), or
(b) are marked, or otherwise identified in the installation
instructions with the intended circuit type, cable type or
specific equipment that is intended to be connected to the
connector. Most ITE output circuits are limited power.
A limited power source is explicitly
defined in UL 60950, and has parameters similar to the power
limiting criteria described in Article 725 and Tables 11(a)
and 11(b). Listed ITE with output circuits supplied by a
limited power source are recognized by Section 725-41(a)(4) as
being equivalent to Class 2 circuits for purposes of applying
Article 725 Class 2 wiring requirements.
Exemptions. Some ITE covered under the
Scope of UL 60950 are not intended for installation in
computer rooms. In fact, some of this equipment cannot easily
be designed to comply with Article 645-based listing
requirements. For equipment that is not intended to be
installed in computer rooms and therefore is not designed for
it, manufacturers are permitted either to mark on the ITE, or
prominently state in their installation instructions that the
equipment is not to be installed in a computer room. However,
most listed ITE is not marked or identified in this manner and
does not have any limitation for installation in computer
rooms.
Most UPSs have not been investigated for
installation in computer rooms. UPSs that are listed to
ANSI/UL 1778 and marked "Suitable for computer room
applications," or similar, are the only UPSs listed for
installation in a computer room.
Telecommunications
With the growth of the Internet and the
widespread installation of communication systems a larger
variety of equipment traditionally installed in
telecommunication equipment closets are now being installed in
computer rooms. Telecommunication equipment, as part of its
listing to UL 60950 also is investigated for installation in
accordance with Article 800, Communications Circuits, and
Article 645.
Fire Protection
Several fire protection requirements apply
to listed ITE intended to be installed in computer rooms that
have their origin in NFPA 75.
• ITE with surface areas greater than
10 sq. ft (0.9 m2) or a single dimension greater than six
feet (1.8 m) are required to have a flame spread rating of
50 or less when tested per either UL 723, ASTM E84, or ASTM
E162.
• Automated information storage
equipment intended to house large quantities of recorded
media (e.g., tapes) inside them are required to be
configured to allow installation of either an automatic
sprinkler system or a gaseous agent extinguishing system
inside the equipment when it is installed in the computer
room.
Photo
7. Fire alarm strobe light in information technology room
Summary
UL 60950 includes specific NEC-based
requirements for ITE that may be installed in a computer room.
As the NEC is revised, UL requirements are reviewed and
updated, as needed. Therefore, AHJs can be confident that
listed ITE has been investigated to comply with the NEC,
including Article 645. Ultimately, AHJs approve listed ITE
used in computer rooms after a determination is made that it
is installed in accordance with the manufacturer-supplied
markings and instructions, and the appropriate UL Guide
Information, and after application of relevant articles of the NEC.
Excerpt
from UL guide information for: Information Technology
Equipment Including Electrical Business Equipment (NWGQ)
General
This
category covers equipment, appliances and systems
rated 600 V or less normally found in offices and
other business establishments, residences (homes),
educational facilities, and other similar environments
Classified as ordinary locations.
Equipment
in this category has been evaluated for installation
in computer/data processing rooms as defined in
Protection of Electronic Computer/Data Processing
Equipment ANSI/NFPA 75, and Article 645 of the
National Electrical Code, ANSI/NFPA 70, unless the
equipment is otherwise identified by a marking or
instruction.
Equipment
Type
Equipment
may be electronic or electromechanical in design or a
combination thereof.
Various
groupings of equipment are included for the
manufacturers, such as:
Information
processing equipment: automated information storage
equipment, central processing units (CPUs), disk
drives, fiber optic transceivers, hand-held computers
(personal assistants), lap-top computers, monitors,
personal computers, plotters, printers, point-of-sale
terminals, scanners, including portable bar-code
scanners, tape drives, workstations.
Telecommunication
equipment: cellular site equipment, cordless telephone
sets, facsimile machines, ISDN systems and telephones,
modems, key telephone systems, private automated
branch exchanges (PABXs), telephone answering
machines, telephone sets, voicemail systems, wireless
telephony systems....
Interconnecting
cable assemblies: cable assemblies intended for use
beneath raised floors of computer rooms. These
assemblies also may be found under Computer
Interconnection Cable Assemblies (DVPJ) in the
Electrical Construction Equipment Directory….
This
category also covers power distribution units (PDUs)
and computer power centers, which are evaluated as
part of the computer system for use exclusively in
computer rooms in accordance with Article 645 of the
National Electrical Code. This equipment is connected
to branch circuits, and it distributes power to other
units in the computer system by means of
interconnecting cable assemblies complying with one or
more of the wiring methods outlined in Article 645 of
the National Electrical Code. Many of these units
require special installation, such as a separate
transformer, special grounding methods, motor
generator equipment, air conditioning, etc. Such
features are covered in the manufacturer’s
installation instructions….
Installation
Some
equipment has been evaluated for installation in a
restricted access location, such as a dedicated
equipment room or telecommunication equipment closet,
where access is limited to trained service personnel.
Such equipment is provided with a marking or
installation instructions which state "To be
installed only in a Restricted Access Location"
or similar wording. If also intended for installation
over a concrete or noncombustible surface, such
equipment will also be marked "Suitable for
mounting on concrete or other noncombustible surface
only" or similar wording.
Equipment
installed in a restricted access location generally
receives power from a centralized dc power source. If
field wiring terminals are not contained in an
internal compartment, both protection of exposed
wiring terminals and wiring methods used for such
equipment are intended to be provided in accordance
with (1) markings on or instructions with the
equipment, and (2) the provisions of Sections 110-18,
110-26, and 110-27 of the National Electrical Code….
When
Listed equipment intended for use with a detachable
power supply cord is not provided with such a cord, a
cord suitable for connection of the equipment to the
branch circuit is to be separately provided.
Equipment
intended to be installed in closed and multi-unit
standard racks and cabinets has been determined to be
suitable for use in ambient temperatures not exceeding
the manufacturer’s recommended ambient temperature
as specified in the equipment’s installation
instructions.
Output
Connectors/Circuits
Class
2 circuits are marked "Class 2." All other
output circuits, including those associated with the
Universal Serial Bus (USB) and IEEE 1394 bus, are
limited power circuits supplied by UL 1950 limited
power sources, unless:
•
the circuits are clearly telecommunication circuits
(e.g., RJ series modular jack, 50 pin commercial
connectors with insulation piercing terminals).
These circuits are limited to telecommunication
network voltages (TNV) and are suitable for
connection to the telecommunication network and
distribution wiring in accordance with Article 800
of the NEC; or
•
the circuits are marked, or otherwise identified in
the installation instructions with the type of
circuit (e.g., Class 1), intended cable type (e.g.,
DP-2) or specific equipment intended to be
interconnected (e.g., mfg/model keyboard).
Limited
power circuits of listed ITE supplied by limited power
sources are recognized by Section 725-41(a)(4) of the
NEC as being equivalent to Class 2 circuits for
purposes of applying Article 725 Class 2 wiring
requirements….
Requirements
The
basic standards used to investigate products in this
category are UL 60950 and UL 1950, "Safety of
Information Technology Equipment."
UL
Mark
The
Listing Mark of Underwriters Laboratories Inc. on the
product is the only method provided by UL to identify
products manufactured under its Listing and Follow-Up
Service. The Listing Mark for these products includes
the UL symbol (as illustrated in the Introduction of
this Directory) together with the word
"LISTED," a control number, and one of the
following category identifiers: "UL 1950,"
"Information Technology Equipment," "NWGQ,"
"I.T.E.," or "Info. Tech.
Equipment," and may also include one of the
following product names, as appropriate:
"Copier," "Modem," "Paper
Shredder," "Personal Computer,"
"Cordless Telephone" or another appropriate
product name as shown in the individual Listing. The
category identifier for field-installed accessories is
provided with the additional word
"Accessory."
Photos
by Melody Jahn, IAEI News. |
Tom Burke serves as
Underwriters Laboratories’ principal engineer for UL’s
Standard for Safety of Information Technology Equipment,
UL 60950, and represents UL on both NEC Code
Making Panel 12 and the Committee on Electronic Computer
Systems for NFPA 75. He is a registered professional
electrical engineer in the state of California.
|
