yes I SEE THE SAME WHICH IS MY MAIN CONCERN WHEN A NUETRAL AND EQC ARE BOND OR CONNECTED TOGETHER INSIDE FIRE PUMP CONTROLLER ON THE EMERGENCY SIDE WILL THAT CREATE AN ODJECTIVE CURRENT SINCE THE BONDING IS ALREADY DONE AT FIRST MAIN BEFORE ATS AND ALSO BEFORE THE GEN
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fire pump controller having pulled neutral and egc from generator having 3 poles ats to the building with same generator feeding ats & fire pump
- Thread starter loco79
- Start date
THERE IS NOT GROUNDED ELECTRODE CONDUCTOR SHOWS IN THE DIAGRAM , ONLY NEUTRAL AND EQCAnytime you have more than one service disconnect enclosure and you use the individual grounding electrode allowance from each of the service disconnects you will have a bond at the electrode that ties the neutral path together
A fire pump service disconnect location separated from the normal power service disconnect is still going to have a GEC bonded to the same grounding electrode system as the other service disconnects in the building
Mike Holt once said as an illustration think of the neutral/ bond like the
common on a 3 way switch
If it's bonded at the gen than it's not bonded at the transfer switch.
If it's bonded at the transfer switch it's not bonded at the gen
In the drawing, the pump controller would be a subpanel of the service. I don't know anything about fire pump codes, so would it be treated any different than a regular subpanel?Anytime you have more than one service disconnect enclosure and you use the individual grounding electrode allowance from each of the service disconnects you will have a bond at the electrode that ties the neutral path together
A fire pump service disconnect location separated from the normal power service disconnect is still going to have a GEC bonded to the same grounding electrode system as the other service disconnects in the building
Mike Holt once said as an illustration think of the neutral/ bond like the
common on a 3 way switch
If it's bonded at the gen than it's not bonded at the transfer switch.
If it's bonded at the transfer switch it's not bonded at the gen
david
Senior Member
- Location
- Pennsylvania
The drawing is not showing the normal power connection to the fire pump controllerIn the drawing, the pump controller would be a subpanel of the service. I don't know anything about fire pump codes, so would it be treated any different than a regular subpanel?
IT DOSENT SHOW NORMAL SIDE BECAUSE MY CONCERN IS FROM GEN TO THE FIRE PUMP CONTROLLER , NOT FROM FPL SIDE THE NORMAL SIDE IS FINE AND COMPLAINT WITH NFPA 70The drawing is not showing the normal power connection to the fire pump controller
THAT WHY IT IS NOT SHOWING IN THE DIAGRAM .
david
Senior Member
- Location
- Pennsylvania
You don't need to yell, you have a building with a (service) neutral in two separate locations.GUYS IS SIMPLE I JUST WANT TO CONFIRM THAT THERE NOT ODJECTIVE CURRENT WITH THIS METHOD OF INSTALLATION
AND THERE NOT WILL BE DANGER IN THE FUTURE TO ANY ONE IN CASE THE OPEN THE EQC AT ANY POINT IN THE CIRCUIT .
The neutral at both locations are bonded to the same electrode which creates a conductive path between the two neutral locations. Add a load and tell me what path does current take to get back to the transformer.
Now look at your gen in the same way as you would the service transformer.
You have a neutral in two separate locations your drawing shows an equipment ground bonding the two neutral locations together by connecting them to the same metal gen housing.
Remove from your drawing one of the equipment grounds. Your two neutral locations would no longer be bonded together through the gen housing.
That would be one path removed
The two neutral locations are still bonded together through the grounding electrode system
When you have a non separately derived system the neutral is not bonded at the gen but is bonded at the transfer switch in your situation involving the fire pump controller the transfer switch at the controller location and the transfer switch you show supplying a panel .
You're inspector said your drawing shows a pathway for objectional current.
Look carefully @ 250.4 (A) (5).
Than look at 250.6 (B) ask the inspector what grounding paths he wants you to remove and document that with his signature
david
Senior Member
- Location
- Pennsylvania
Now in simplicity the inspector is correct the neutral from your source is the effective fault clearing path. It is required to create that path even though the fire pump itself does not need a neutral
The key here is not bonding the gen neutral at the gen location.
That was stated many times to you throughout this thread
The key here is not bonding the gen neutral at the gen location.
That was stated many times to you throughout this thread
so much like it going to the fire pump controller only needs one path for low impedance for effective ground fault back to the source which will be in this case gen set , is it not ? thank youYou don't need to yell, you have a building with a (service) neutral in two separate locations.
The neutral at both locations are bonded to the same electrode which creates a conductive path between the two neutral locations. Add a load and tell me what path does current take to get back to the transformer.
Now look at your gen in the same way as you would the service transformer.
You have a neutral in two separate locations your drawing shows an equipment ground bonding the two neutral locations together by connecting them to the same metal gen housing.
Remove from your drawing one of the equipment grounds. Your two neutral locations would no longer be bonded together through the gen housing.
That would be one path removed
The two neutral locations are still bonded together through the grounding electrode system
When you have a non separately derived system the neutral is not bonded at the gen but is bonded at the transfer switch in your situation involving the fire pump controller the transfer switch at the controller location and the transfer switch you show supplying a panel .
You're inspector said your drawing shows a pathway for objectional current.
Look carefully @ 250.4 (A) (5).
Than look at 250.6 (B) ask the inspector what grounding paths he wants you to remove and document that with his signature
Say what? The drawing shows the service on the left, the ATS in the middle and the pump controller on the right. The MBJ is at the service.The drawing is not showing the normal power connection to the fire pump controller
but also in the field installation it has service utility in the normal side of the fire pump controller as wellSay what? The drawing shows the service on the left, the ATS in the middle and the pump controller on the right. The MBJ is at the service.
that side is fine and complaint with nfpa 70 .
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
That was an ipad typo. It was supposed to say is showed a neutral ground bond.The OP shows the bond in the main panel and a solid neutral transfer switch. And then the neutral bonded to ground again at the pump controller
david
Senior Member
- Location
- Pennsylvania
I'm not exactly saying that.so much like it going to the fire pump controller only needs one path for low impedance for effective ground fault back to the source which will be in this case gen set , is it not ? thank you
I'm saying remove one of the equipment grounds bonded to the gen housing and you are not doing anything to really address objectional currents since the grounding electrode system is bonded at both service neutral locations
I said the key here is not bonding the gen neutral at the gen location.
I also now realize the inspector never raised the issue of objectional currents.
He raised the issue of needing the neutral from the gen to the fire pump controller. For an effective fault clearing path.
The objectional current issue was raised on your end
thank youI'm not exactly saying that.
I'm saying remove one of the equipment grounds bonded to the gen housing and you are not doing anything to really address objectional currents since the grounding electrode system is bonded at both service neutral locations
I said the key here is not bonding the gen neutral at the gen location.
I also now realize the inspector never raised the issue of objectional currents.
He raised the issue of needing the neutral from the gen to the fire pump controller. For an effective fault clearing path.
The objectional current issue was raised on your end