Line side tap question

[icebox]

My line side taps were put in with B taps.

[sensij]

My line side taps were put in with B taps.

Yes, there are ways to avoid the 6 connector version that was suggested. Those methods are not mandated by code, and the poco's policy for line side taps would probably be designed around the worst case, not the best.

[jflorey2]

Even in that case the tap does not have an OCPD protecting it. Electricity from the grid flows through the taps *before* it reaches the breaker.

Uh - OK. By that measure, no load center has OCPD's protecting them, because power flows through the main lugs BEFORE reaching any breakers. But in common usage, people consider load centers to have overcurrent protection.

[inetdog]

Uh - OK. By that measure, no load center has OCPD's protecting them, because power flows through the main lugs BEFORE reaching any breakers. But in common usage, people consider load centers to have overcurrent protection.

A main-lug-only load center does not have overcurrent protection for the bus bars, and so need to have upstream OCPD.
FWIW you cannot consider the wires as tap wires and then the bus bars as a continuation of the tap, since NEC requires that the incoming tap conductors terminate directly at an OCPD.
A main breaker panel does have no OCPD between the lugs on the main breaker and the inside of the breaker case, but that is ignored by the NEC since the breaker and associated lugs are designed for that purpose.
And, of course, incoming service conductors also do not have upstream OCPD which protects them, but service conductors have their own sizing and location rules separate from tap rules.
Technically the wires from the meter load side to whatever are not tap wires, they are service conductors.

[foo1bar]

Uh - OK. By that measure, no load center has OCPD's protecting them, because power flows through the main lugs BEFORE reaching any breakers. But in common usage, people consider load centers to have overcurrent protection.

On the load side (after the main breaker) it does have overcurrent protection.
On the line side there isn't protection.

My understanding is that being before the main breaker (and therefore no OCPD) is what defines a tap as a "line side" tap.

[inetdog]

On the load side (after the main breaker) it does have overcurrent protection.
On the line side there isn't protection.

My understanding is that being before the main breaker (and therefore no OCPD) is what defines a tap as a "line side" tap.

More precisely it is before the service disconnect (and associated OCPD) that makes it a line side tap. The service disconnect is usually the main breaker of the service panel, but not always.

The NEC also allows the service disconnect(s) to be the individual breakers of a main lug only (MLO) panel which is rated for service use. As long as there are not more than six such breakers.
But your typical residential panel also has labels stating that it is listed for service use only if a main breaker is installed.

[jflorey2]

On the load side (after the main breaker) it does have overcurrent protection.
On the line side there isn't protection.

Correct. So the only accessible output is protected. Calling it "unprotected" is therefore inaccurate.

My understanding is that being before the main breaker (and therefore no OCPD) is what defines a tap as a "line side" tap.

"Line side tap" means it comes before the main breaker for the house panel. There is no requirement that it be unprotected.

[foo1bar]

So the only accessible output is protected. Calling it "unprotected" is therefore inaccurate.

"Line side tap" means it comes before the main breaker for the house panel. There is no requirement that it be unprotected.

If it's before the main breaker it is by definition unprotected.
(Well, I suppose there's potentially self-reseting fuses or such at the transformer that's feeding that service drop - but generally people would still consider that unprotected since it's 100's of amps that the transformer will supply)

The "line side tap" is the spot where the 3 wires/conductors come together - the wire to the meter, the wire towards the inverter, and the wire towards the main breaker.

Even if the line side tap and a breaker/disconnect are packaged together into one box the line side tap is still not protected by an OCPD. Only the wires AFTER that breaker are protected. With a nicely packaged/manufactured solution like you linked to, the risk of something going wrong with that tap is obviously pretty minimal, and it doesn't really matter as much that it's not protected by an OCPD.

[sensij]

Even if the line side tap and a breaker/disconnect are packaged together into one box the line side tap is still not protected by an OCPD. Only the wires AFTER that breaker are protected. With a nicely packaged/manufactured solution like you linked to, the risk of something going wrong with that tap is obviously pretty minimal, and it doesn't really matter as much that it's not protected by an OCPD.

Your definition of "protected" is not consistent with NEC, UL, or any other standard of which I am aware. It is certainly good design practice to locate the OCPD as close to the energy source as possible, but the entire circuit is considered protected, not just the conductors behind the ocpd.

[inetdog]

Your definition of "protected" is not consistent with NEC, UL, or any other standard of which I am aware. It is certainly good design practice to locate the OCPD as close to the energy source as possible, but the entire circuit is considered protected, not just the conductors behind the ocpd.

And that is where you are wrong, or at least muddling the concept of protected.
Usually the word protected refers to something which is protected against any overcurrent which is greater than the carrying capacity of the wire. And to wire which is protected at its source end.
The NEC recognizes a critically different circuit called a tap, which is also safe but does not have both of those elements present.
A tap is protected at its rated ampactiy only at the end of the wire most distant from the source. And it must have some upstream protection, even if it is not at or below the wire rating. Depending on the length and location of the tap wire, the upstream breaker cannot exceed roughly three times the carrying capacity of the wire.
If there is no upstream protection then there is nothing to apply the factor of three to and therefore no possibility of a legal tap.

Service conductors are to some extent protected by primary protection of the service transformer but:
1. The nature and rating of that protection are typically unknown to the customer.
2. That POCO protection is designed to protect the primary voltage transmission lines or perhaps even the transformer, but not the service wires on the transformer secondary. The secondary protection of the transformer is provided by the service conductors melting, perhaps in a spectacular way, in the case of an short circuit.
3. For that reason service conductors, with a very limited exception whose details are left in the hands of AHJs to interpret, are not allowed to run inside a building.

The line side (supply side) tap for PV is tap in name only and is not authorized by any tap rules in the NEC. Instead those "tap" wires are simply extensions of the service conductors. An AHJ could without much stretching, require the conductors upstream of the PV disconnect to be no smaller than the main service conductors coming from POCO. I have little doubt that the internal wiring of the cited device leading up to the breaker is sized to safely handle the 100A or 200A rating of the service to which they are attached.
In that, it is no more and also no less protected than the service drop conductors themselves.