Purpose of the weeb
- Thread starter csoc64
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jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I agree with Zee. I always thought it was bit odd that Enphase showed the weeb as an option at all. They were clearly counting on the idea that some AHJs wouldn't believe there was a need for a GEC.
It remains to be seen how AHJs will react to Enphase's assertion that the new M250 doesn't require a GEC.
It remains to be seen how AHJs will react to Enphase's assertion that the new M250 doesn't require a GEC.
OK, so here's the $64 question, what's the down side of having installed systems without GEC's?
Jben,
Very apropo that you bring up what the purpose of the WEEB is for an Enphase micro-inverter. We just figured it out, it was a mystery......
It is to bond the racking to the inverter, not vice versa. That is to say, in order to continue the EGC and bonding of the rack - thru the rail with the WEEB, into the inverter body, which in turn is bonded with the grounding wire provided inside the AC cabling.
In other words: you can put WEEB washers on the module clamps, a WEEB on the micro, and you are done with bonding.
Still need the GEC. That is not bonding.
But no WEEB splices from rail-end to rail-end horizontally; and no EGC bare copper nor WEEB-Lugs running vertically from one row to another row of rails!
Am i off my rocker?
Re. the Enphase M250 and whether GEC is needed
http://enphase.com/global/files/M250-with-IG.pdf
pretty exciting.
http://enphase.com/global/files/M250-with-IG.pdf
pretty exciting.
OK, so please help me understand this. What gets connected to the GEC? Just the microinverters? Does the GEC need to be continuous back to the panel, or can it be combined with the EGC in the j-box on the roof (assuming it is sized large enough). Can you advise how the GEC is typically installed. Much thanks for your advice.Jben,
Very apropo that you bring up what the purpose of the WEEB is for an Enphase micro-inverter. We just figured it out, it was a mystery......
It is to bond the racking to the inverter, not vice versa. That is to say, in order to continue the EGC and bonding of the rack - thru the rail with the WEEB, into the inverter body, which in turn is bonded with the grounding wire provided inside the AC cabling.
In other words: you can put WEEB washers on the module clamps, a WEEB on the micro, and you are done with bonding.
Still need the GEC. That is not bonding.
But no WEEB splices from rail-end to rail-end horizontally; and no EGC bare copper nor WEEB-Lugs running vertically from one row to another row of rails!
Am i off my rocker?
Typically:
GEC from inv. to inv.
Same GEC continues thru rooftop j-box down to MSP.
This single GEC IS UNSPLICED UNCUT CONTINUOUS THRU-OUT.
I use THWN-2 stranded #8 and strip insulation at each enphase lug. The stranded and insulated is easy to pull in conduit.
EGC (bare copper #10 solid) and WEEBS must bond every rail and every module.
This rooftop EGC can be spliced TO GEC in rooftop j-box. Split-bolt. Point is that EGC is cut, not GEC.
Hence you have a single #8 GEC/EGC running in conduit down off roof.
Use racking listed for WEEBS and enphase.
Just use a WEEb on each enphase to bond the rail to the module.
WEEb on every module clamp (don't be cheap, put it on every clamp, i say) to bond module to rail.
Use a WEEB-Lug and #10 wire on any rail that is not bonded by above.
Stop and reconsider: has every rail, module and inverter been bonded?
GEC from inv. to inv.
Same GEC continues thru rooftop j-box down to MSP.
This single GEC IS UNSPLICED UNCUT CONTINUOUS THRU-OUT.
I use THWN-2 stranded #8 and strip insulation at each enphase lug. The stranded and insulated is easy to pull in conduit.
EGC (bare copper #10 solid) and WEEBS must bond every rail and every module.
This rooftop EGC can be spliced TO GEC in rooftop j-box. Split-bolt. Point is that EGC is cut, not GEC.
Hence you have a single #8 GEC/EGC running in conduit down off roof.
Use racking listed for WEEBS and enphase.
Just use a WEEb on each enphase to bond the rail to the module.
WEEb on every module clamp (don't be cheap, put it on every clamp, i say) to bond module to rail.
Use a WEEB-Lug and #10 wire on any rail that is not bonded by above.
Stop and reconsider: has every rail, module and inverter been bonded?
Thanks so much for the info. I'm doing a little less head scratching now. Just a couple of clarification questions. What does MSP refer to? Are we talking about the main bonding point in the panel? Also, does 690.47(C)(3) allow a single conductor to serve as both EGC and GEC, provided it is sized per 250.166?
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
MSP is Main Service Panel.
Regarding 690.47(C)(3), you have it basically correct. It allows a single conductor to serve as both EGC and GEC, provided it is sized for the larger of either requirement. On residential systems this almost always means going with the minimum #8 for a GEC according to 250.166, since the 250.122 requirement for an EGC is smaller up to 60A.
Just out of curiosity, how did you solve the mystery? Did the solution come from Enphase?Jben,
Very apropo that you bring up what the purpose of the WEEB is for an Enphase micro-inverter. We just figured it out, it was a mystery......
It is to bond the racking to the inverter, not vice versa. That is to say, in order to continue the EGC and bonding of the rack - thru the rail with the WEEB, into the inverter body, which in turn is bonded with the grounding wire provided inside the AC cabling.
In other words: you can put WEEB washers on the module clamps, a WEEB on the micro, and you are done with bonding.
Still need the GEC. That is not bonding.
But no WEEB splices from rail-end to rail-end horizontally; and no EGC bare copper nor WEEB-Lugs running vertically from one row to another row of rails!
Am i off my rocker?
shortcircuit2
Senior Member
- Location
- South of Bawstin
csoc64...what brand/model solar modules are on the job?
no. not from enphase.
just the perpetual search for less work.
American Choice 250W modules with Enphase M215 microinverters
The WEEB clip positively bonds the Enphase inverter metallic case to a metallic rail as part of the grounding system by penetrating any oxides or coatings on the rail or inverter case. It is quick and easy.
Reference Enphase M215 and Engage cable: The M215 inverter has 4 wires - 2 line (red, black), 1 green equipment grounding conductor (EGC), one white grounded conductor (N). The green wire (EGC) IS NOT bonded to the metallic inverter case. The inverter also has a built-in lug.
The Enphase Engage cable also has 4 wires of the same colors. Using standard wiring methods will bring the circuit back to the main panelboard . Of course, the green wire is not bonded to the white (N) until at the main service panel where they are bonded together.
Since all exposed metallic parts of the PV system must be bonded together in an equi-potential plane as part of the grounding system,
the WEEB clip easily bonds the inverter metal case to the metallic rail in a similar manner as a copper water pipe.
With the inverter case bonded to the metallic rail, the metallic rail(s) are then bonded together using approved lugs or clips to the grounding electrode conductor (GEC) which is then bonded to the grounding electrode near the service panel.
In lieu of a WEEB clip. a properly sized copper conductor can be bonded to each inverter case (as the GEC) using the provided lug. Each rail supporting the PV panels is also bonded to the grounding system by an approved lug holding the GEC.
Using WEEB clips is much faster and cheaper than running long lengths of copper wire to all the components.
As an aside, WEEB clips can also be used to bond the metallic frames of the PV panels to the grounding system instead of using copper conductor and lugs.
Reference Enphase M215 and Engage cable: The M215 inverter has 4 wires - 2 line (red, black), 1 green equipment grounding conductor (EGC), one white grounded conductor (N). The green wire (EGC) IS NOT bonded to the metallic inverter case. The inverter also has a built-in lug.
The Enphase Engage cable also has 4 wires of the same colors. Using standard wiring methods will bring the circuit back to the main panelboard . Of course, the green wire is not bonded to the white (N) until at the main service panel where they are bonded together.
Since all exposed metallic parts of the PV system must be bonded together in an equi-potential plane as part of the grounding system,
the WEEB clip easily bonds the inverter metal case to the metallic rail in a similar manner as a copper water pipe.
With the inverter case bonded to the metallic rail, the metallic rail(s) are then bonded together using approved lugs or clips to the grounding electrode conductor (GEC) which is then bonded to the grounding electrode near the service panel.
In lieu of a WEEB clip. a properly sized copper conductor can be bonded to each inverter case (as the GEC) using the provided lug. Each rail supporting the PV panels is also bonded to the grounding system by an approved lug holding the GEC.
Using WEEB clips is much faster and cheaper than running long lengths of copper wire to all the components.
As an aside, WEEB clips can also be used to bond the metallic frames of the PV panels to the grounding system instead of using copper conductor and lugs.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Says who?
There's a pretty clear argument to be made that the GEC must be continuous or irreversibly spliced from the inverter to the grounding electrode, per the code. (That is based on the article 100 definition of a GEC, 690.47, and 250.64.) Perhaps a connection to a grounding busbar is sufficient per 690.47(C)(3), but a WEEB is definitely not an irreversible splice.
As a matter of opinion, I think that it's a bit over the top that we have (in effect) more stringent grounding requirements for microinverter systems operating at less than 50VDC than we do for string inverter systems at up to 600VDC. But as far as the current code, it doesn't allow a WEEB to be a GEC. With that said, I understand that the 2014 will introduce some changes in this regard.
shortcircuit2
Senior Member
- Location
- South of Bawstin
UL 467
UL 467
The WEEB is a UL 467 grounding and bonding device listed by ETL...
UL 467
The WEEB is a UL 467 grounding and bonding device listed by ETL...
A WEEB a way
A WEEB a way
No matter what the WEEB is actually for, on our solar install crew it is required to sing this song when installing them:
"A WEEB-a-way A WEEB-a-way A WEEB-a-way A WEEB-a-way
On the roof, the mighty roof, the WEEB gets torqued tonight
On the roof, the mighty roof, the WEEB gets torqued tonight"
Now you'll have that stupid song in your head all day. Muwahahahaaa!
A WEEB a way
No matter what the WEEB is actually for, on our solar install crew it is required to sing this song when installing them:
"A WEEB-a-way A WEEB-a-way A WEEB-a-way A WEEB-a-way
On the roof, the mighty roof, the WEEB gets torqued tonight
On the roof, the mighty roof, the WEEB gets torqued tonight"
Now you'll have that stupid song in your head all day. Muwahahahaaa!
shortcircuit2
Senior Member
- Location
- South of Bawstin
Nobody torques their WEEBS. They use impact guns.
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