Jockey Pump Tap conductor

[elec_eng]

I have a 1 1/2 HP (480V 3Ph) Jockey pump that is tapped off of 75HP Fire pump feeder (#3/0) that is directly connected to the secondary side of the transformer.

What would be the size of Jockey Pump tap condcutor? Can it be #12? Does the tap rule apply here?

I was showing the same #3/0 conductor for the jockey pump in order not to worry about the tap rule but the Jockey pump mfgr is saying that their controller can not accept #3/0.

 

[charlie]

In my opinion, the 10' or 25' tap rule will apply. However, you will not be able to protect the tap from overload at the load end of the tap. :smile:

 

[elec_eng]

In my opinion, the 10' or 25' tap rule will apply. However, you will not be able to protect the tap from overload at the load end of the tap. :smile:

Charlie,

The fire pump feeder is unprotected conductor as well as the jockey pump conductor. How does the tap rule still apply?

 

[RUWired]

are these service conductors or tap conductors tapping a tap

 

[elec_eng]

are these service conductors or tap conductors tapping a tap

The fire pump feeder is directly connected to the secondary side of utility transformer so it would be service conductors. The jockey pump feeder is tapped right before the fire pump controller.

 

[charlie]

. . . How does the tap rule still apply?

It doesn't, I was wrong and in too much of a hurry. Please note below.

. . . so it would be service conductors. . .

I agree.

 

[elec_eng]

If the transformer is not a utility transformer and a customer owned, would it make any diffenece?

Now then the fire pump feeders are not service conductors anymore. They become building feeders. They are still unprotected conductors since they are secondary conductors of the transformer.

Will it make a difference on a jockey pump tap feeder? Can I still tap #12 wires off of #3/0 fire pump feeders?

 

[RUWired]

If the transformer is not a utility transformer and a customer owned, would it make any diffenece?

A lot of inspectors i know still treat these as service conductors.

Now then the fire pump feeders are not service conductors anymore. They become building feeders. They are still unprotected conductors since they are secondary conductors of the transformer.

If the secondary conductors are not service conductors and you tap the transformer anywhere other than at the transformer, you'll have a 240.21(C) violation

Will it make a difference on a jockey pump tap feeder? Can I still tap #12 wires off of #3/0 fire pump feeders?

SDS taps are ok at the transformer. Service conductor taps are ok per 230.82(5) providing the tap conductors are not less than the rating of the disconnect for the tap.

 

[elec_eng]

If the secondary conductors are not service conductors and you tap the transformer anywhere other than at the transformer, you'll have a 240.21(C) violation.

I don't see how this will be a violation of 240.21(C). It doesn't say that you can tap the transformer secondary condutors.

240.2 Definition

Tap Conductors: A tap condutor is defined as a conductor, other than service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as decribed elsewhere in 240.4.

Tapping off of the transformer secondary conductor is not a tap conductor per defintion because it doesn't have an overcurrent protection ahead of it point of supply. The transformer secondary conductor is a unprotected conductor. So, the tap rule shouldn't apply here..what am I missing?

SDS taps are ok at the transformer.

Is that a tap? Or another set of secondary conductors?

 

[Pierre C Belarge]

The set of conductors that are supplied from the secondary of a transformer are considered tap conductors as per the definition in 240.2.

One is not permitted to tap a tap. Which means one is not permitted to tap the conductors on the secondary side of transforemers.

 

[elec_eng]

The set of conductors that are supplied from the secondary of a transformer are considered tap conductors as per the definition in 240.2.

I am still on 2005 but in the definiton I quoted, I don't see the secondary of a transformer as a tap conductor. Is it shown on 2008?

 

[RUWired]

If you start with article 240.4(E)3 and follow through the trail, it describes secondary conductors as tap conductors and also not being able to tap the tap conductor.

240.4 Protection of Conductors.
(E) Tap Conductors. Tap conductors shall be permitted to be protected against overcurrent in accordance with the following:
(3) 240.21, Location in Circuit
Overcurrent protection shall be provided in each ungrounded circuit conductor and shall be located at the point where the conductors receive their supply except as specified in 240.21(A) through (H). Conductors supplied under the provisions of 240.21(A) through (H) shall not supply another conductor except through an overcurrent protective device meeting the requirements of 240.4.
(C) Transformer Secondary Conductors.

 

[elec_eng]

If you start with article 240.4(E)3 and follow through the trail, it describes secondary conductors as tap conductors and also not being able to tap the tap conductor.

Got it..Thanks!!