Line side tap question

[icebox]

Searched but couldn't find anything decisive on the topic...

Why are Line side taps frowned upon?

[sensij]

Frowned upon by whom?

If you mean, why do some power companies discourage them, I think it is because many msp designs are not intended to support a tap between the meter and main supply breaker. Sdg&e's renewable meter adapter makes the tap right off of the meter socket... naturally, they want control of that to prevent meter tampering.

[icebox]

Maybe I'm mistaken then.

I couldn't see what's not to like about it, quick and cheaper than replacing the main panel to feed in if it's required.

[sensij]

Power companies might also not like them because the rating of the service feed needs to be considered and possibly upgraded, while a load side connection won't affect the feed at all.

[foo1bar]

Maybe I'm mistaken then.

I couldn't see what's not to like about it, quick and cheaper than replacing the main panel to feed in if it's required.

It's a connection where there is no OCPD (no fuses, no breakers)
So if the tap is not done in a way that will hold up for decades you have the potential for very bad things.

In addition there are cases where there is no wires between the meter and the main breakers - just metal busses going from the meter socket in one half of the box to the breakers in the other half. And in those cases, there is no way to securely attach to those busses which doesn't modify them (and modifying them would void the UL listing)

[sensij]

It's a connection where there is no OCPD (no fuses, no breakers)
So if the tap is not done in a way that will hold up for decades you have the potential for very bad things.

No... (legal) line side taps require dedicated OCPD. A fused disconnect is typically used.

[icebox]

No... (legal) line side taps require dedicated OCPD. A fused disconnect is typically used.

Agreed, my line side tap has an OCPD from the inverter to the feeder lines.

[foo1bar]

No... (legal) line side taps require dedicated OCPD. A fused disconnect is typically used.

line side taps don't have an OCPD protecting them - period.
If they were on the other side of an OCPD they wouldn't be a "line side tap"
The fused disconnect that is used *is* an OCPD - but it doesn't protect the connection where the line side tap is.
Effectively there isn't protection on that connection - so if that tap fails there can be 100s of amps flowing.

Now a properly done line-side tap isn't really a risk - but the question the OP posed was "Why are Line side taps frowned upon?" - and that would be one reason.

[ButchDeal]

Maybe I'm mistaken then.

I couldn't see what's not to like about it, quick and cheaper than replacing the main panel to feed in if it's required.

often the service panels in Southern CA that are center feed 100a do not physically have room for a line side tap.

[icebox]

line side taps don't have an OCPD protecting them - period.
If they were on the other side of an OCPD they wouldn't be a "line side tap"
The fused disconnect that is used *is* an OCPD - but it doesn't protect the connection where the line side tap is.
Effectively there isn't protection on that connection - so if that tap fails there can be 100s of amps flowing.

Now a properly done line-side tap isn't really a risk - but the question the OP posed was "Why are Line side taps frowned upon?" - and that would be one reason.

I understand what you mean now, but the tap failing is similar to the main feed lug failing, there are too many 'what if's to say any system of interconnection is 100% safe.

[foo1bar]

I understand what you mean now, but the tap failing is similar to the main feed lug failing, there are too many 'what if's to say any system of interconnection is 100% safe.

Similar in result if it fails - yes.

Similar in likelyhood of it happening - IMO no.
A main feed lug has 2 connections per phase - the meter and the main breaker input.
A line-side tap has 6 connections per phase
meter
tap-toward-meter
tap-toward-inverter
tap-toward-main breaker
main breaker input
inverter (actually fused disconnect between tap and inverter)

And I think the POCO could believe (rightly or wrongly) that the people who do a line-side-tap are less-experienced/more-prone-to-error than people installing a meter pan and main breaker.

I'm not saying it can't be done correctly and safely - just pointing out what at least some of the reasoning may be for it not being as desirable a solution as others.

[jflorey2]

line side taps don't have an OCPD protecting them - period.

Still incorrect. Here's an example of the line side tap adapters used around here:

http://connectder.com/products

Note the breakers.

[inetdog]

Still incorrect. Here's an example of the line side tap adapters used around here:

http://connectder.com/products

Note the breakers.

I would call that a special case, in that the unit combines the tap function with the PV disconnect function.
The conductors which are accessible, to which the GTI gets connected, are NOT tap conductors at all. The line side tap function is integrated entirely within the tap/disconnect combo. From the point of view of the GTI and the customer wiring it is no different than connecting to a main or sub panel.

And I could see some POCOs not approving it, depending on how it gets connected to the service conductors.

[foo1bar]

"line side taps don't have an OCPD protecting them - period."

Still incorrect. Here's an example of the line side tap adapters used around here:

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.

In that product the tap and breaker are all packaged into one unit - and presumably QC'd and tested at the factory before shipping. So I can see it being even less risk than a generic line-side-tap. And possible to retrofit into spots where there is no spot to do a tap normally, like an all-in-one meter+main-panel combo.

[inetdog]

And possible to retrofit into spots where there is no spot to do a tap normally, like an all-in-one meter+main-panel combo.

But is requires that POCO accept foreign equipment attached in an area which includes unmetered wires.
Some POCOs are selling and installing similar units, maintaining their own control of that section of wiring.