Fire pump - old question

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I have not seen any Code article that stated otherwise.
As to it's being grounded by an equipment ground or a grounded service conductor, that would depend on the type installation.
 
I have not seen any Code article that stated otherwise.
As to it's being grounded by an equipment ground or a grounded service conductor, that would depend on the type installation.

Can you clarify more? If we consider ATS/controller as a main disc., we do not need to run equipment ground wire right?
 
I assume the fire pump ats is 4-pole type with switched neutral in order we can ground it?
 
My opinion: If the ATS is service rated and is being used as a service disconnect then the nuetral could also be the ground.
If the service disconnect is ahead of the neutral, then grounding would be seperate.
I find nothing in Art 695 that would cause me to think differently.

If the ATS is 4 pole and switching the neutral, your generator would be a tretead as a seperately derived system.
 
I assume the fire pump ats is 4-pole type with switched neutral in order we can ground it?
If the fire pump transfer switch is considerd service equipment and is required to have the grounded conductor brought to it, why would you want to switch it. Most likely the neutral is not even needed for the fire pump. Unless its one big single phase pump.

Rick
 
The fire ATS has two coming feeder, normal feeder tap to secondary of building utility xfmr, emergency feeder was fed out of emergency generator (considering separate devrived system) So, ATS should has switched neutral?
 
The fire ATS has two coming feeder, normal feeder tap to secondary of building utility xfmr, emergency feeder was fed out of emergency generator (considering separate devrived system) So, ATS should has switched neutral?

My point is the neutral is not needed on the load side of the ATS for the fire pump, so why are you using a switched neutral transfer switch, or even bringing the neutral conductor out from the generator.

Rick
 
If we treate fire pump ats as a separate service, should we gound the ATS?
Then, do we need neutral wire to bind to ground at ATS?
 
If we treate fire pump ats as a separate service, should we gound the ATS?
Then, do we need neutral wire to bind to ground at ATS?

anbm, article 250.24(C) states that the grounded conductor (neutral) shall be brought to the service disconnect, but it only needs to be sized per 250.24(C)1 using table 250.66.
A grounding conductor does not need to brought in with the grounded conductor.
At the ATS, the main bonding jumper will need to be installed on the service grounded conductor.

Rick
 
In Kentucky, the inspector made us insulate the neutral from the transformer (totally seperate service from transformer), which was also the ground because it was not needed as a neutral. We had to use the neutral/ground from the main building service to ground the fire pump. He was concerned that there would be a parallel of the neutrals with the fire pump and the building which I can kinda see his point. But he also made us bond on the load side of a four pole ground fault transfer switch, which makes the ground fault function of the switch virtually useless.
 
In Kentucky, the inspector made us insulate the neutral from the transformer (totally seperate service from transformer), which was also the ground because it was not needed as a neutral. We had to use the neutral/ground from the main building service to ground the fire pump. He was concerned that there would be a parallel of the neutrals with the fire pump and the building which I can kinda see his point. But he also made us bond on the load side of a four pole ground fault transfer switch, which makes the ground fault function of the switch virtually useless.
I wouldn't agree with the inspector on this one if i understand what you described. You have two utility power sources for the fire pump transfer switch. You installed the main bonding jumper on the load side of the switched neutral. So if they are both utility sources, then they are both energized all the time and the OCPD for each service is the A.T.S. If a fault happens in source two while the switch is in the preferred source one position, how is the fault path going to return to source two transformer.

Rick
 
anbm, article 250.24(C) states that the grounded conductor (neutral) shall be brought to the service disconnect, but it only needs to be sized per 250.24(C)1 using table 250.66.
A grounding conductor does not need to brought in with the grounded conductor.
At the ATS, the main bonding jumper will need to be installed on the service grounded conductor.

Rick


RUwired, if we treat fire pump ATS as a separate service entrance disconnect/board, we need to ground it or bonded to building grounding system (water metal pipe, building steel, rod, etc).

Then, when fire pump ATS is switched to emergency power source (serving from emergency generator), will this create ground loop violation? Because we bonded the generator to building grounding system as it is separate devried system (assume both generator and fire stays inside)

Same thing happens when fire pump ATS on normal utility power.
 
They are both fed from the same transformer, before he would allow the neutral to be bonded at the fire pump service he would require that a separate transformer be set just for the pump. He was concerned over the neutrals being paralleled because both are connected to the same grounding electrodes, the ocp would still work though, even if one is running on source one, and the other on source two. The GFP would not work though because the fault current would return through the GF CT instead of going around it. We questioned this practice, so the inspector called in the state inspector who required the same thing, he said that's what they required statewide.
 
RUwired, if we treat fire pump ATS as a separate service entrance disconnect/board, we need to ground it or bonded to building grounding system (water metal pipe, building steel, rod, etc).

Then, when fire pump ATS is switched to emergency power source (serving from emergency generator), will this create ground loop violation? Because we bonded the generator to building grounding system as it is separate devried system (assume both generator and fire stays inside)

Same thing happens when fire pump ATS on normal utility power.

anbm, first i would point out that article 250.58 allows the use of a common grounding electrode. The way i look at this set up is the switched neutral terminal is not needed in this ats. It has no apparent purpose especially if theres no load requiring it. The grounded conductor from the utility transformer would be bonded in the ats. From the generator the equipment grounding conductor (if main breaker is at gen set) equipment bonding jumper if not is used for grounding but would be in parallel with the grounding electrode conductor, but that is not a violation. The grounded conductor (neutral) from the gen set is not required. If for some reason the ats load equipment required the grounded conductor, the switched neutral would be put in use.
Rick
 
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If the fire pump locates inside building (concrete structure not building steel), how do you bond the fire pump/ats to grounding sytem? Drive a ground rod?
 
If the fire pump locates inside building (concrete structure not building steel), how do you bond the fire pump/ats to grounding sytem? Drive a ground rod?

You would use the same grounding electrode system that is being used by the main service to the building. See 250.58

Where an ac system is connected to a grounding electrode in or at a building or structure, the same electrode shall be used to ground conductor enclosures and equipment in or on that building or structure.
Where separate services, feeders, or branch circuits supply a building and are required to be connected to a grounding electrode(s), the same grounding electrode(s) shall be used.
Two or more grounding electrodes that are bonded together shall be considered as a single grounding electrode system in this sense.
 
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