25 FT Tap Rule

[mbrooke]

Meter sockets have a rather high SCCR. But true SCCR should always be checked. Not sure what the resistance has to do with it.

When a fault occurs anywhere before the OCPD the tap feeds into, the total circuit impedance can not delay the upstream device.

Tap conductors are allowed by code on the premise they will carry short circuit current very briefly.

 

[jap]

We don't know the resistance or I2R withstand of the meter socket, busbar, ect.

Hopefully your just joking right?

JAP>

 

[mbrooke]

Hopefully your just joking right?

JAP>

Just stating the code's reasoning and physics behind it.

The idea is that tap conductors must be protected from short circuit current as well as overload current. The difference is overload protection can be moved down stream as no one can "plug" anything into the tap conductors, however the same can not be done with short circuit protection when using fuses or standard TM breakers.

 

[electrofelon]

When a fault occurs anywhere before the OCPD the tap feeds into, the total circuit impedance can not delay the upstream device.

Tap conductors are allowed by code on the premise they will carry short circuit current very briefly.

I wish you would stop with this. There is no code requirement to do this. It's probably really confusing for people who come on here trying to learn and they read your post and then think they have to investigate the "resistance of their meter socket".

 

[mbrooke]

I wish you would stop with this. There is no code requirement to do this. It's probably really confusing for people who come on here trying to learn and they read your post and then think they have to investigate the "resistance of their meter socket".

No need to, code technically doesn't want you terminating in a meter socket. I'm just explaining why.

 

[electrofelon]

No need to, code technically doesn't want you terminating in a meter socket. I'm just explaining why.

Yes we are discussing/debating whether a tap can pass thru a meter socket. But this is larger than that. You keep implying that we need to calculate things like loop impedance and clearing time and you posting in this thread is just more of you pushing that BS.

 

[mbrooke]

Yes we are discussing/debating whether a tap can pass thru a meter socket. But this is larger than that. You keep implying that we need to calculate things like loop impedance and clearing time and you posting in this thread is just more of you pushing that BS.

I have not implied that in this thread. Code does not allow terminating taps into a meter socket, even though this rule is frequently misapplied in some areas.

Code wants tap conductors electrically short as possible- a meter socket is nothing more than an extension of a tap conductor instead of ending it at an OCPD.

 

[jap]

I have not implied that in this thread. Code does not allow terminating taps into a meter socket, even though this rule is frequently misapplied in some areas.

Code wants tap conductors electrically short as possible- a meter socket is nothing more than an extension of a tap conductor instead of ending it at an OCPD.

I'd have to say every termination in a meter socket is a tap.

The line side conductors are an unprotected tap from the utility company's transformer.
The load side conductors are an unprotected tap to the line side of a service disconnect or tenant main.

If the meter socket is an extension of a tap conductor then there shouldn't be an issue with it.

JAP>

 

[mbrooke]

Correct- but you have to keep in mind tap rules apply to feeders, not service conductors. The OP has a fused main disconnect.

 

[jap]

Correct- but you have to keep in mind tap rules apply to feeders, not service conductors. The OP has a fused main disconnect.

The whole point is to protect the tap conductor.

How can a tap made from a feeder be less protected than a tap made from the load side of a utility meter socket to the line side of a service disconnect or tenant main?

JAP>

 

[mbrooke]

The whole point is to protect the tap conductor.

How can a tap made from a feeder be less protected than a tap made from the load side of a utility meter socket to the line side of a service disconnect or tenant main?

JAP>

You bring up a really food point. Why code doesn't allow that I have no idea to be honest.

 

[jap]

You bring up a really food point. Why code doesn't allow that I have no idea to be honest.

Well we are talking about "Feeders" you know....

JAP>

 

[mbrooke]

Well we are talking about "Feeders" you know....

JAP>

Auto type/correct has failed me again... and again Either that I had a Freudian slip

 

[don_resqcapt19]

I'd have to say every termination in a meter socket is a tap.

The line side conductors are an unprotected tap from the utility company's transformer.
The load side conductors are an unprotected tap to the line side of a service disconnect or tenant main.

If the meter socket is an extension of a tap conductor then there shouldn't be an issue with it.

JAP>

If there is no upstream service disconnect, they are simply service conductors and none of the rules in 240.21(B) apply. Those rules only apply where the conductors on the line side of the meter are feeder conductors, which is the case where there is a service disconnect between the service point and the meter.

 

[jap]

If there is no upstream service disconnect, they are simply service conductors and none of the rules in 240.21(B) apply. Those rules only apply where the conductors on the line side of the meter are feeder conductors, which is the case where there is a service disconnect between the service point and the meter.

I know all that.

Just saying the terminations in the meter do nothing to change the fact that the tap conductors (if sized properly) and the meter rating (if sized properly) are still protected by the overload device or set of fuses they land on regardless.

JAP>

 

[electrofelon]

- a meter socket is nothing more than an extension of a tap conductor instead of ending it at an OCPD.

Exactly. The meter socket is just an extension of the tap conductor. The tap conductor ultimately terminates on the required OCPD. I am not seeing anything saying the tap conductor must be continuous without a splice, transition or joint.

 

[don_resqcapt19]

I know all that.

Just saying the terminations in the meter do nothing to change the fact that the tap conductors (if sized properly) and the meter rating (if sized properly) are still protected by the overload device or set of fuses they land on regardless.

JAP>

No it changes nothing, but I am not going to change my opinion that it is a violation of what is required by the language in 240.21(B).

We are not going to agree here.

 

[mopowr steve]

Whoa, whoa, whoa wait a minute.
That’s really not a service disconnect, it’s an emergency disconnect.
Now discuss

 

[electrofelon]

Whoa, whoa, whoa wait a minute.
That’s really not a service disconnect, it’s an emergency disconnect.
Now discuss

 

[don_resqcapt19]

Whoa, whoa, whoa wait a minute.
That’s really not a service disconnect, it’s an emergency disconnect.
Now discuss

It is not an emergency disconnect if there are more than two meters.