NEC 2020 section 705.11(C)

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hhsting

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NEC 2020 section 705.11(C) says PV AC disconnect need to be readily accessible when supplied from line side of the service disco.

Attached sketch shows electric room the main service disco building is inside and the AC PV disco is outside. Would the attached sketch comply with NEC 2020 Section 705.11(C) or not readily accessible part?

036fb619c58f7224dc1eceba7d247f89.jpg
 
hhsting said:
NEC 2020 section 705.11(C) says PV AC disconnect need to be readily accessible when supplied from line side of the service disco.

Attached sketch shows electric room the main service disco building is inside and the AC PV disco is outside. Would the attached sketch comply with NEC 2020 Section 705.11(C) or not readily accessible part?

036fb619c58f7224dc1eceba7d247f89.jpg
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I was just about to ask a very similar question. There are two items that throw me off with 705.11(C). First there appears to be a typo. The second sentence reads, "If fuses are not integral" shouldn't it read "If fuses are integral" just like the language in Article 230?

Secondly, the section goes into detail about the connection to the service on the outside of the building, giving where the overcurrent devices can be located inside or outside the building. But when discussing the connection inside the building it only gives the distance requirement and does not use the term readily accessible. However, I think the intent was to have this readily accessible even though it doesn't explicitly say it. My understanding would be you could have your overcurrent device mounted outside the building and you would just follow the conductor length requirements.

On a separate note, If you had a conductor length over 16.5' and had to use cable limiters, is there another location that they could be mounted, besides the tap location, where you could easily replace them without having to cut them off and re-crimp the conductors to new cable limiters?
 
cyriousn said:
I was just about to ask a very similar question. There are two items that throw me off with 705.11(C). First there appears to be a typo. The second sentence reads, "If fuses are not integral" shouldn't it read "If fuses are integral" just like the language in Article 230?

Secondly, the section goes into detail about the connection to the service on the outside of the building, giving where the overcurrent devices can be located inside or outside the building. But when discussing the connection inside the building it only gives the distance requirement and does not use the term readily accessible. However, I think the intent was to have this readily accessible even though it doesn't explicitly say it. My understanding would be you could have your overcurrent device mounted outside the building and you would just follow the conductor length requirements.

On a separate note, If you had a conductor length over 16.5' and had to use cable limiters, is there another location that they could be mounted, besides the tap location, where you could easily replace them without having to cut them off and re-crimp the conductors to new cable limiters?
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Man, I just re-read the section and now I've confused myself. 705.11(C)(1) Reads...

With an overcurrent device located within 10 ft. of conductor length in dwelling units and 16.5 ft in other than dwelling units from the points of connection to the service.

The key words being IN. Are we to assume that these need to be inside? Or do the length parameters only apply?
 
Pretty sure that 'in' should be read as 'in or on.' Previous codes made no distinction between dwellings and non-dwellings and the word 'in' thus did not appear. Since the first version of this code section I've understood the length limit to apply regardless of location.
 
cyriousn said:
Man, I just re-read the section and now I've confused myself. 705.11(C)(1) Reads...

With an overcurrent device located within 10 ft. of conductor length in dwelling units and 16.5 ft in other than dwelling units from the points of connection to the service.

The key words being IN. Are we to assume that these need to be inside? Or do the length parameters only apply?
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The two list items in 705.11(C) only apply where the power source output conductors make their connection to the service conductors inside the building.
Where the power source output conductors are connected to the service conductors outside of the building, the OCPD must be either at a readily accessible point outside of the building or at the first readily accessible location where the conductors enter the building.

This is very much like the rule for service equipment, if located inside, to be located at a readily accessible location "nearest the point of enetrance" of the service conductors.
 
cyriousn said:
I was just about to ask a very similar question. There are two items that throw me off with 705.11(C). First there appears to be a typo. The second sentence reads, "If fuses are not integral" shouldn't it read "If fuses are integral" just like the language in Article 230?
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It's not a typo. It's just saying that if you have a fuse enclosure without a switch and a switch at a supply side interconnection, the switch has to be between the fuses and the interconnection point. It makes sense; otherwise you would have to call in a utility shutdown to install or change the fuses.
 
don_resqcapt19 said:
The two list items in 705.11(C) only apply where the power source output conductors make their connection to the service conductors inside the building.
Where the power source output conductors are connected to the service conductors outside of the building, the OCPD must be either at a readily accessible point outside of the building or at the first readily accessible location where the conductors enter the building.

This is very much like the rule for service equipment, if located inside, to be located at a readily accessible location "nearest the point of enetrance" of the service conductors.
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Based on the sketch provided by OP, it appears that the connection to the service conductors is made inside the building and the disconnect outside the building, no?
 
ggunn said:
It's not a typo. It's just saying that if you have a fuse enclosure without a switch and a switch at a supply side interconnection, the switch has to be between the fuses and the interconnection point. It makes sense; otherwise you would have to call in a utility shutdown to install or change the fuses.
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Okay, that makes sense but what is the scenario where the fuses not being in the disconnect has it's advantage? Do most major equipment manufactures make a fuse box that would be wired in series to the conductors? I just tried looking it up and all that came up was non-fused disconnects....
I thought the verbiage was trying to have a similar meaning to the verbiage in 230.91 but that is more about having the fuses in the disconnect be after the break in the switch.
 
cyriousn said:
Okay, that makes sense but what is the scenario where the fuses not being in the disconnect has it's advantage? Do most major equipment manufactures make a fuse box that would be wired in series to the conductors? I just tried looking it up and all that came up was non-fused disconnects....
I thought the verbiage was trying to have a similar meaning to the verbiage in 230.91 but that is more about having the fuses in the disconnect be after the break in the switch.
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Actually I had just a scenario. We are supply side interconnecting in an electrical room which has no room for a disco and is more than 71' from any outside wall (cable limiters are out under the 2020 NEC). We thought of just installing a small enclosure with fuses to satisfy the distance requirement from interconnection to OCPD, but this code article prevents that. With good reason, I might add.
 
ggunn said:
Actually I had just a scenario. We are supply side interconnecting in an electrical room which has no room for a disco and is more than 71' from any outside wall (cable limiters are out under the 2020 NEC). We thought of just installing a small enclosure with fuses to satisfy the distance requirement from interconnection to OCPD, but this code article prevents that. With good reason, I might add.
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Sounds like quite the pickle to be in. Was there any possibility of a load side connection or connecting into the feeder off the transformer without having to dump tons of $$$ on the project?
 
ggunn said:
Actually I had just a scenario. We are supply side interconnecting in an electrical room which has no room for a disco and is more than 71' from any outside wall (cable limiters are out under the 2020 NEC).
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So why do you need the disconnect outside, what's wrong with inside, not in the electrical room (no space), but within 20m of cable length of the interconnection in the electrical room (with cable limiters within 5m)?

Cheers, Wayne
 
wwhitney said:
So why do you need the disconnect outside, what's wrong with inside, not in the electrical room (no space), but within 20m of cable length of the interconnection in the electrical room (with cable limiters within 5m)?

Cheers, Wayne
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The utility requires an outside disconnect, but that's not the problem; we could have two of them. We are investigating our options but it's an office building and the customer doesn't want the disco visible. We may be able to install a backfed breaker in the switchgear on the line side of the service disconnect, but that wouldn't be easy. Life has gotten "interesting".
 
In this case, does the disconnect serve as both the 705.11(C) overcurrent device and the lockable utility accessible disconnect? There's no need for two devices, correct?
 
cyriousn said:
In this case, does the disconnect serve as both the 705.11(C) overcurrent device and the lockable utility accessible disconnect? There's no need for two devices, correct?
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There has to be a PV system disconnecting means at or near the supply side point of interconnection per the NEC, and there has to be one outside at a readily accessible location per the requirements of the AHJ (Centerpoint Energy). The POI is in the electrical room in the middle of the building and the PV system is on multiple carport structures.
 
cyriousn said:
Man, I just re-read the section and now I've confused myself. 705.11(C)(1) Reads...

With an overcurrent device located within 10 ft. of conductor length in dwelling units and 16.5 ft in other than dwelling units from the points of connection to the service.

The key words being IN. Are we to assume that these need to be inside? Or do the length parameters only apply?
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705.11(C) indicates the following text just before that section:
"Where the power source output circuit conductors make their connection to the service inside a building, they shall be protected with one of the following methods."

This means that given a POI in indoor equipment, you are still subject to these length constraints even if you exit the building to get to your first disconnect. It doesn't matter that part of the length is outside; what matters is whether the POI is inside or not. The gray area is if your POI is in equipment mounted on a building's exterior wall. In that case, I would recommend assuming the length constraint applies.

When your POI is in outside equipment that is either pad-mounted on an outdoor slab, or mounted on a free-standing framework, that is when these length constraints wouldn't apply.
 
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