Project Number: 228730 WWTE SCADA Upgrades
Issue Date: August 2017 Nashua, NH
3.02 BONDING FOR OTHER TRADES
A.
Signal raceways, water piping, heating piping and metallic air ducts shall be
bonded together and to the grounding conductor with No. 8 soft drawn bare solid
conductors. Connections to pipes shall be made with cast clamps of like material
as the pipes to which attached, to ducting terminated in a secure manner by best
practical means, bonding across any flexible or insulated connections.
All bonding conductors shall be installed in a neat manner properly shaped for
contour of surface involved and properly supported. At locations remote from the
main service entrance panel boards, bond to the largest raceway nearby.
3.03 FIELD TESTING
A.
Measure ground resistance without the soil being moistened by any means other
than natural precipitation or natural drainage or seepage and without chemical
treatment or other artificial means of reducing natural ground resistance. Perform
tests by the three-point fall of potential method in accordance with Section 9.03 of
IEEE 81. Simple moisture addition is not acceptable.
Ground/resistance maximum values shall be as follows:
1. Equipment rated 500 kva and less: 10 ohms.
2. Equipment rated 500 kVA to 1000 Kva: 5 ohms.
3. Equipment rated over 1000 kVA: 3 ohms.
4. Unfenced substations and pad mounted equipment: 5 ohms.
5. Fence Grounds: 10 ohms.
Where ground resistances exceed specified values, and if directed, modify the
grounding system to reduce resistance values.
END OF SECTION
GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS
WOODARD & CURRAN 26 05 26-4
