Fire pump controller

H

hhsting

Senior Member
Location
Glen bunie, md, us
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Junior plan reviewer
I have multi campus style building where customer owned transformer primary delta 13.2k to secondary wye 277/480V is feeding the fire pump controller/ats/breaker and jockey pump controller. The fire pump and jockey pump are both 480V three phase load

Engineer wants to bring neutral from the secondary side of the customer owned transformer to the fire pump controller/ats/breaker all in one but tells me their is no neutral lug in fire pump controller/ats/breaker all in one. He says there is only ground lug in fire pump controller/ats/breaker all in one.

Can he bring the neutral from secondary of customer owned transformer and land in ground lug since there is no neutral lug in fire pump controller/ats/breaker all in one or not?
 
It is a service. (kinda) look at it like that. MBJ and all. Or in this case, it is called a SBJ. But really, it just looks like a service.

I unknowingly used to say "SSBJ" and 3 phases but was corrected by someone in CMP 2. It should look, and mirror, what a typically service should look like. So long as the transfer switch / fire pump controller is SUSE.
 
I was going to edit the above post, but realized I should just add to it.

I think, since this is a customer owned transformer, you might be allowed to wire it like you would any ol' sub panel after a transformer. My issue was where it was technically two services being provided by the utility. The fire pump was tapped ahead of the main, and as such, the fire pump controller / ATS required a MBJ in that "service" because it was a "service disconnect".

You situation might allow for it to be done differently.
 
If the transformer was outside, I would advocate for wiring it like a service. Connecting the neutral, to GEC, to case in the fire pump controller / ATS. No different than I would the switchgear that was inside.

If the transformer is inside. Well, I might still do it in the fire pump controller / ATS. It depends on the layout, and how the transformer is looking.

But don't forget the building GES. You might need to connect that.
 
Elect117 said:
If the transformer was outside, I would advocate for wiring it like a service. Connecting the neutral, to GEC, to case in the fire pump controller / ATS. No different than I would the switchgear that was inside.

If the transformer is inside. Well, I might still do it in the fire pump controller / ATS. It depends on the layout, and how the transformer is looking.

But don't forget the building GES. You might need to connect that.
Click to expand...

Existing Customer owned transformer is outside. Their is no system bonding jumper in existing transformer. Wye is not connected to the grounding electrode conductor in the existing customer owned transformer outside.

I know what you all say have system bonding jumper in existing transformer but that is not option.

Fire pump comtroller/ats/breaker all in one is new and inside building.

Would that make a difference if I land neutral in the ground lug since there is no neutral lug of the fire pump controller or not?
 
hhsting said:
Existing Customer owned transformer is outside. Their is no system bonding jumper in existing transformer. Wye is not connected to the grounding electrode conductor in the existing customer owned transformer outside.

I know what you all say have system bonding jumper in existing transformer but that is not option.

Fire pump comtroller/ats/breaker all in one is new and inside building.

Would that make a difference if I land neutral in the ground lug since there is no neutral lug of the fire pump controller or not?
Click to expand...

Anyone?


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hhsting said:
Existing Customer owned transformer is outside. Their is no system bonding jumper in existing transformer. Wye is not connected to the grounding electrode conductor in the existing customer owned transformer outside.

I know what you all say have system bonding jumper in existing transformer but that is not option.
Click to expand...

Ignoring that noncompliance.....



Yes. it will look like a service with MBJ/SBJ with GEC/GES added to the fire pump controller / transfer switch.
 
hhsting said:
Existing Customer owned transformer is outside. Their is no system bonding jumper in existing transformer. Wye is not connected to the grounding electrode conductor in the existing customer owned transformer outside.
Click to expand...
Then you need to run a neutral to the fire pump controller and install a system bonding jumper. It it will also require a supply side bonding jumper back to the transformer and a service rated transfer switch. (not 100 % sure, there may be a way around the service rated fire pump controller. I am saying service rated as that would have provisions for a main/system bonding jumper.)
A far easier approach would be to install a system bonding jumper at the transformer and run the phase conductors and supply side bonding jumper between the fire pump controller and the transformer.
 
don_resqcapt19 said:
Then you need to run a neutral to the fire pump controller and install a system bonding jumper. It it will also require a supply side bonding jumper back to the transformer and a service rated transfer switch. (not 100 % sure, there may be a way around the service rated fire pump controller. I am saying service rated as that would have provisions for a main/system bonding jumper.)
A far easier approach would be to install a system bonding jumper at the transformer and run the phase conductors and supply side bonding jumper between the fire pump controller and the transformer.
Click to expand...

If i bring neutral sized in compliance with NEC 2017 Table 250.102(C)(1) to fire pump controller from customer owned transformer then why I also need to bring supply side bonding jumper?


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hhsting said:
If i bring neutral sized in compliance with NEC 2017 Table 250.102(C)(1) to fire pump controller from customer owned transformer then why I also need to bring supply side bonding jumper?


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Click to expand...
A supply side bonding jumper is required back to the transformer to provide a fault clearing path for a secondary winding short to the laminations or transformer case as there is no other path. A supply side bonding jumper is always required between a transformer and the first OCPD.
 
hhsting said:
Existing Customer owned transformer is outside. Their is no system bonding jumper in existing transformer. Wye is not connected to the grounding electrode conductor in the existing customer owned transformer outside.

I know what you all say have system bonding jumper in existing transformer but that is not option.

Fire pump comtroller/ats/breaker all in one is new and inside building.

Would that make a difference if I land neutral in the ground lug since there is no neutral lug of the fire pump controller or not?
Click to expand...
Normally off a utility transformer, it would be the same, whether it was the neutral or egc, they both would connect at the same spot in the transformer. But if the neutral originates after the main disconnect, and the main disconnect is groundfault protected, it may give nuisance tripping, or possibly nullification of the ground fault protection.
 
don_resqcapt19 said:
Then you need to run a neutral to the fire pump controller and install a system bonding jumper. It it will also require a supply side bonding jumper back to the transformer and a service rated transfer switch. (not 100 % sure, there may be a way around the service rated fire pump controller. I am saying service rated as that would have provisions for a main/system bonding jumper.)
A far easier approach would be to install a system bonding jumper at the transformer and run the phase conductors and supply side bonding jumper between the fire pump controller and the transformer.
Click to expand...

Assuming that engineer might be interested in putting neutral to ground bond in the transformer then how do you size bonding jumper from ground bus bar in transformer to the transformer case? Based on primary overcurrent protection device size and NEC 2017 Table 250.122 or based on something else?
 
hhsting said:
Assuming that engineer might be interested in putting neutral to ground bond in the transformer then how do you size bonding jumper from ground bus bar in transformer to the transformer case? Based on primary overcurrent protection device size and NEC 2017 Table 250.122 or based on something else?
Click to expand...
Table 250.102(C)(1) based on the sum of the cross sectional area of the secondary conductors.
 
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