TM 5-8113/AFM 88-9, Chap. 3
3-4. Bonding
35. Grounding. Grounding is the process of con-
necting one or more metallic objects and g-rounding
a. Bonding is the process of connecting two or
conductors to a ground electrode or system. A metal-
more conductive objects together by means of a con-
lic object also may be grounded by bonding to an-
ductor. Bonding is done to minimize voltage differ-
other metallic object that is already connected to the
ences and impedances of joints. Bonding conductors
ground. Grounding conductors within the building
normally will be uninsulated. When bonding conduct-
will be bonded separately to static electricity bonding
ors are used between movable objects, and connec-
jumpers or other bonded metals, and connected be-
tions are disconnected frequently, they will be of the
low finished grade to an appropriate grounding elec-
flexible conductor or strap type. When concealed or
trode or system. No fewer than two grounding con-
mechanically protected, bonding conductors may be
ductors will be provided for connection to grounding
No. 10 AWG copper wire; otherwise No. 6 AWG cop-
electrodes at opposite corners of any building. For
per wire or larger will be used. Bonding for other fa-
buildings having more than a total of 1,600 square
cilities will conform with NFPA No. 70, and U L 467,
feet of protected area, one grounding conductor-
unless otherwise required in paragraph 3-9. The fol-
electrode arrangement will be provided at each cor-
lowing guide will be used for determining objects to
ner of the building. Steel framing members of the
be bonded, in conformance with paragraph 3-2:
building and metal sides that are electrically bonded
--For permanently installed underground
and not used for lightning protection may be as part
built-in equipment having metal housing and movable
of the grounding conductor system. Ground rods will
or portable equipment having ungrounded metal
be not less than 5/8 inch in diameter, 8-foot long cop-
housing; bond to attached or unattached fixed adjoin-
per or copper-clad rods driven so tops are not less
ing metal.
than 6 inches below finished grade, except as other-
--For movable or portable equipment nor-
wise required herein. The electrical power grounding
mally having ungrounded metal housing located in
system will be extended and connected to the static
room or area where protection of operating and main-
electricity grounding system.
tenance personnel is required regularly; provide con-
ductive flooring as described below.
36. Hazardous locations. Electrical design will
--For movable or portable normally ungrounded
incorporate the requirements of the using service rel-
equipment having nonconductive housing and no ac-
ative to hazardous materials, equipment and contain-
cessible grounding terminal; provide bonding termi-
ers to the extent that information is furnished to en-
nal for portable type connection.
able the construction contractor to proceed with full
--For classified equipment; bond in conform-
understanding of static electricity protection provi-
ance with paragraph 39. Electrically conductive con-
sions. Classifications will conform to NFPA No. 70,
tainers with explosive and flammable contents shall
unless otherwise authorized by the using service. For
be grounded. In bonding explosive and flammable
Air Force facilities, classifications of hazardous areas
contents of containers, including nonconducting liq-
of hangars, docks and POL areas will conform to
uids stored in electrically insulated containers, it may
AFM 88-15. For Army facilities, classifications for
be necessary to insert a conductive electrode having
POL areas will conform to AR 415-22.
a bonding terminal on the exterior of the container.
37. Petroleum oil lubricants (POL) facilities.
The electrode material will be chemically inert to the
This paragraph pertains to static electricity protec-
stored ingredients and the container. Such an ar-
tion for pumping, distribution, fueling and refueling
rangement will be specified only by the using service.
storage and miscellaneous handling facilities for
Whenever such electrode is used, it will be of a de-
Army facilities. Fueling and refueling of fixed wing
signed which will preclude its being broken off during
aircraft on the ground is discussed in paragraph 311.
handling of containers.
Recommendations contained in NFPA No. 77, will be
b. Before securing any bond, it is necessary to in-
included in each project design of these facilities as
sure electrical continuity by removing any paint, oil,
appropriate. Prior to and during fueling of other than
dirt or rust to present an electrically clean contact
fixed wing aircraft, the refueling hose nozzle must be
surface. In providing a bond for a frequently moving
bonded to the plane by means of a short bond wire
body such as a metal door, hinged shelf or table, not
and clip, without reliance upon a separate static elec-
less than two separated flexible bonding straps will
tricity grounding system. Air Force designs will be
be provided. Bonds will not be made to gas, steam,
in accordance with the requirements of AFM 85-16.
oil, air, or hydraulic lines, nor to sprinkler system
piping or metallic bodies connected to lightning pro-
38. Weapon systems. Where electromagnetic
tection system, except as required below finished
pulse (EMP) or electromagnetic sheilding protection
grade, as described below.
is included in the design of any weapons system,
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