Dear Experts,
Situation : In implementing electrical plans by various design companies.
I am running an insulated Equipment Grounding Conductor from MCC
grounding busbar to motorised equipments (pumps compressors HVAC equip)
along with the phase wires terminating on motor ground lug or terminal
box itself.
Also on the same equipments, I am running a "Bare Cooper Wire? from the pump chasis or metal framing to a ground bus on the room wall wherein two BCW going to each ground bus such that a loop arrangement is formed and in other utility rooms as well, each end of the loop going to the grounding
electrode (ring & rods or grids) outside. At same time a bond jumper is connecting the pump and the motor chasis.
The ff are several issues I want to clarify,
1. What do I call this "bare copper wire from motor chasis to a ground
bus" ,seemingly second type of ground wire? (Can I call it "Equipotential Bonding Conductor" then define it via NFPA-77,780 since the " bonding jumper " described in the NEC is still for continuity of fault current path.)
2. Where in the NEC states that it is needed, required or safe to
install this? Is it always required?
3. I suspect that this wire can defeat the purpose of GFrelays that fault current running on the EGC will too weak to de activate the breakers since fault current will be divided via "second ground wire".
if relays are not set properly. Is it correct?
4. If its not in the NEC then it is not a violation to remove it. What is the IEEE opinion on this.
5. For unclassified locations such as roof deck, pump & HVAC machine rooms, electrical or switchgear rooms, Is it mandatory to used two types of grounding one for EGC and another for surge potential discharge?
( my views:
I wish the NEC had used the term " Equipment Bonding Conductor " so that it will coincide as description on sect.250.4 (3) and the intent of the EGC. and reserve the term "Equipment Grounding Conductor" or EGC for the purpose as described in the 250.4 (2) that can include the requirements for the lighting and static requirement. Since the Bonding and Grounding are distinct terms being used in the NEC. the term EGC is being used to serve the purspose of Bonding & Grounding. Would you agree? I know many documents will have to be revised, it?s a lot of work.
But since Static & Lightning Hazards are not always present in all cases The EGC (with short bonding jumpers as required) can be used for the Bonding &Grounding describe in 250.4 (2) & (3) in which voltage & fault current dissipation Hazards in the Electrical sys. are always present. Am I correct?)
Note: Still trying to find a copy of the following references, also have not read them yet :
NFPA 77-2000, Recommended Practice on Static Electricity; NFPA 780-2004, Standard for the Installation of Lightning Protection Systems; and API RP 2003-1998, Protection Against Ignitions Arising Out of Static Lightning and Stray Currents.
Situation : In implementing electrical plans by various design companies.
I am running an insulated Equipment Grounding Conductor from MCC
grounding busbar to motorised equipments (pumps compressors HVAC equip)
along with the phase wires terminating on motor ground lug or terminal
box itself.
Also on the same equipments, I am running a "Bare Cooper Wire? from the pump chasis or metal framing to a ground bus on the room wall wherein two BCW going to each ground bus such that a loop arrangement is formed and in other utility rooms as well, each end of the loop going to the grounding
electrode (ring & rods or grids) outside. At same time a bond jumper is connecting the pump and the motor chasis.
The ff are several issues I want to clarify,
1. What do I call this "bare copper wire from motor chasis to a ground
bus" ,seemingly second type of ground wire? (Can I call it "Equipotential Bonding Conductor" then define it via NFPA-77,780 since the " bonding jumper " described in the NEC is still for continuity of fault current path.)
2. Where in the NEC states that it is needed, required or safe to
install this? Is it always required?
3. I suspect that this wire can defeat the purpose of GFrelays that fault current running on the EGC will too weak to de activate the breakers since fault current will be divided via "second ground wire".
if relays are not set properly. Is it correct?
4. If its not in the NEC then it is not a violation to remove it. What is the IEEE opinion on this.
5. For unclassified locations such as roof deck, pump & HVAC machine rooms, electrical or switchgear rooms, Is it mandatory to used two types of grounding one for EGC and another for surge potential discharge?
( my views:
I wish the NEC had used the term " Equipment Bonding Conductor " so that it will coincide as description on sect.250.4 (3) and the intent of the EGC. and reserve the term "Equipment Grounding Conductor" or EGC for the purpose as described in the 250.4 (2) that can include the requirements for the lighting and static requirement. Since the Bonding and Grounding are distinct terms being used in the NEC. the term EGC is being used to serve the purspose of Bonding & Grounding. Would you agree? I know many documents will have to be revised, it?s a lot of work.
But since Static & Lightning Hazards are not always present in all cases The EGC (with short bonding jumpers as required) can be used for the Bonding &Grounding describe in 250.4 (2) & (3) in which voltage & fault current dissipation Hazards in the Electrical sys. are always present. Am I correct?)
Note: Still trying to find a copy of the following references, also have not read them yet :
NFPA 77-2000, Recommended Practice on Static Electricity; NFPA 780-2004, Standard for the Installation of Lightning Protection Systems; and API RP 2003-1998, Protection Against Ignitions Arising Out of Static Lightning and Stray Currents.
