Grounding And Bonding In Electrical Systems

Grounding And Bonding In Electrical Systems

The requirements for grounding and bonding in Section 10 of the Canadian Electrical Code (CEC) are the most important rules in the entire document. But they may also be among the least understood.

Grounding and bonding design and installation is not a complex subject but it must be done in such a manner as to accomplish the following:

(a)

to protect life from the danger of electric shock and property from damage by bonding to ground non-current-carrying metal systems.

(b)

to limit the voltage on a circuit when it is exposed to higher voltages than that for which it is designed.

(c)

in general to limit ac circuit voltages-to-ground to 150 V or less on circuits supplying interior wiring systems.

(d)

to facilitate the operation of electrical apparatus and systems, and

(e)

to limit the voltage on a circuit that might otherwise occur through exposure to lightning.

Once installed, the integrity of the grounding and bonding system may be rarely checked. Thus the code contains prescriptive requirements on materials and installations. Rule 10-802 contains very specific requirements for the material system grounding conductors. The grounding conductor of a wiring system "shall be copper", according to the CEC.

Rule 10-804 requires that the material for bonding conductors be:

(a)

a conductor of copper or other corrosion-resistant material, insulated or bare.

(b)

a copper busbar or steel pipe.

(c)

rigid metal conduit, except that a separate copper conductor shall be installed within the conduit.

(d)

electrical metallic tubing, except that a separate conductor required by item (a) shall be installed within the tubing.

(e)

the copper or aluminum sheath of mineral-insulated cable or any conductor of a mineral-insulated cable if it is permanently marked at the time of installation so that it can be readily distinguished from conductors that are not used as bonding conductors, except that if the sheath is of aluminum in an underground run or in a location where materials having a deteriorating effect may come in contact with the aluminum metal corrosion-resistant protection suitable for the corrosive conditions encountered shall be provided.

(f)

the sheath of aluminum-sheathed cable or copper-sheathed cable, except that if the sheath is used in underground runs or in locations where materials having a deteriorating effect may come in contact with the metal, corrosion-resistant protection suitable for the corrosive conditions encountered shall be provided.

(g)

other metal raceways or cable armour as provided for in Rule 10-618.

Grounding And Bonding In Electrical Systems


> SECTION 1 - GROUNDING and BONDING SYSTEMS


> SECTION 2 - GROUNDING ELECTRODES

> SECTION 3 - HIGH VOLTAGE INSTALLATIONS

> SECTION 4 - BONDING

> SECTION 5 - HIGH RESISTANCE GROUNDING (HRG)

> SECTION 6 - MOTOR GROUNDING

> SECTION 7 - COMPUTER SYSTEMS GROUNDING and BONDING - POWER QUALITY

> SECTION 8 - WIND TURBINE GROUNDING SYSTEMS

> SECTION 9 - GROUNDING SOLAR PHOTOVOLTAIC SYSTEMS

> SECTION 10 - THE "UFER" GROUND

> SECTION 11 - CONCLUSION