Do I need a main over current device? -- Tap conductor, Service conductor

[zemingduan]

Please see picture below. The reviewer gives us a comment says main over current device is required ahead of the taps. He didn't specify where do we need the main over current device. But IMO we don't need any extra over current device anywhere by code.(3 locations are marked out by 1,2,3 )


Some detailed questions:

1. At location 1. We don't need a tap box. We just need a junction box or maybe even a junction box is not needed, since there are 2 sets of service conductors coming in and one set feeds the 300 amps meter, another set feeds the rest of the equipment. Am I right?

2. At location 2. We don't need a main over current device for this bus conductor tapped from the service conductor. IMO, the bus conductor is service conductor rather than a tap conductor(even though it is tapped from service conductor). Conductor before the service disconnect means is service conductor according to the definition of service conductor in NEC 100. Thus we don't need to apply 240.21. Am I right?

3. At location 3. We do need a disconnect since conductor for panel EP is a tap conductor and over 25ft.

4. Is it a thumb up design to use a disconnect for this bus conductor, but it's not required by code?

I am a new graduated student and just working on electrical design for a year. I know you guys are awesome. First time posting, I am looking forward to your ideas. Thanks!

 

[zemingduan]

Here is an additional question:

Can these breakers for units panels work as service disconnect means(the bus is grounded, these breakers are located in electrical room)? Is a service disconnect mean required right after the tap box? (In my opinion these breakers can work as service disconnect means, that's why I think this bus conductor is service conductor in question 2)

 

[electrofelon]

You are correct:

1 and 2 do not need an OCPD PROVIDED you meet the requirements in 230.40, 230.70, 230.71, 230.72. Look over them. Basically your disconnects need to be grouped unless these are different occupancies.

#3 appears to be a regular feeder tap, so you would need to meet one of the rules in 240.21(B).

 

[zemingduan]

You are correct:

1 and 2 do not need an OCPD PROVIDED you meet the requirements in 230.40, 230.70, 230.71, 230.72. Look over them. Basically your disconnects need to be grouped unless these are different occupancies.

#3 appears to be a regular feeder tap, so you would need to meet one of the rules in 240.21(B).

Thanks for your reply. Do you think the first tap is ahead of the rest service disconnect means and violate the provision 230.82(5)?

 

[electrofelon]

Thanks for your reply. Do you think the first tap is ahead of the rest service disconnect means and violate the provision 230.82(5)?

A service disconnect for 230.82(5) does not need to be grouped with the others, if that is what you are asking.

 

[jaggedben]

Thanks for your reply. Do you think the first tap is ahead of the rest service disconnect means and violate the provision 230.82(5)?

No.

Does the first tap serve one of the items mentioned in that section? If so then the section you quoted permits it.

Otherwise the first tap is just going to one of the sets of service entrance conductors permitted by 230.40 Exception 2.

The two sections do not contradict each other.

 

[zemingduan]

No.

Does the first tap serve one of the items mentioned in that section? If so then the section you quoted permits it.

Otherwise the first tap is just going to one of the sets of service entrance conductors permitted by 230.40 Exception 2.

The two sections do not contradict each other.

Do you know whether jockey pump is included in the 230.82(5)? Is jockey pump considered as a fire pump equipment? I know it's a pressure maintenance equipment.