add-ons

Disqualifications: Auto re-roofs include: wood shake, metal shingle, clay tile, more than one layer of shingles, and singles on flat roofs (less than 10 degree pitch.

Roof Repair: Used when we need to repair some of the roof material but the roof is in overall good condition.

Re-roof: Used when the overall condition of the roof is not suitable for installation.

Rake: The slanting edge of a gable roof at the end wall of the house (eave to ridge)

Ridge: The line of intersection at the top between the opposite slopes or sides of a roof

Eave: The lower border of a roof that overhangs the wall

Hip: The external angle formed by the meeting of two sloping sides of a roof that have their wall plates running in different directions

Valley: The place of meeting of two slopes of a roof that form on the plan a reentrant angle

1 | EXISTING EQUIPMENT

MODULES AND INVERTERS

The designer will always need to know the modules and inverters that are used in the existing system.

Locate the labeling on these components:
- Module specifications sticker will be on the back side of the module; it may require that you to lift one of the modules up to get this info.
Microinverters will also be underneath adjacent to each module.
- When a central string inverter is used, it is still likely that the modules are using DC Optimizers that will be located where microinverters are usually located.
- In either case, get the specification sticker for either microinverters or DC Optimizers

String Inverters:

A string inverter is a single inverter that converts DC power generated by PV modules into AC power at a single point. It will basically be the combiner panel and inverter in one (see the first image on the right).

They are sometimes used with DC Optimizers to maximize efficiency across arrays, but it is possible, under the right conditions that the strings will come directly from the modules to the central inverter with no optimizers in between.
- As stated above, always get photos of the stickers on any DC optimizer.
- DC Optemizers will be attached to each module when in use.
Make sure to get the specifications sticker for the string inverter as well.

This is an example of what the labeling will look like for these components.

COMBINER EQUIPMENT

Just as with any electrical equipment on a standard residential account, we need photos of the enclosure opened up with the wiring exposed:

Show where wires are coming from and going to
Get close up on the breakers in the panel
Get the specification sticker.

PV UTILITY EQUIPMENT

PV utility equipment will include any AC disconnect or PV meter in between the combiner panel and the point of interconnection.

We need photos of this equipment opened up showing the wiring and any fuses.
We will need photos of the equipment in line with the rest of the equipment.

For more information on PV Electrical Equipment, click here.

2 | STRUCTURAL PHOTOS

ROOF MOUNTS

We need to watch out for improper mounting. There are two main scenarios you can see from in the attic:

2.5" lag screws landing directly in flat rafters or directly in the sheathing:
- Basically, if you can see the mounting screws sticking through like this, that's a red flag
lag screws blowing out through the side of a typical truss or rafter.
- This will be less common but we're looking for the same thing: screws coming through at an angle and busting through one side of the rafter.

NEW RED FLAGS AND DAMAGE

Just as with any new residential account, we need to screen for any new red flags or damage in the attic. refer to Structural Red Flags & Damage for more information on this.

INTERIOR HOME RUN

Document any wire runs coming from exterior junction boxes connected to the module strings:

Check that any penetrations appears to be sealed off and there is no water damage.
Follow that path where the wire enters and exits the attic space.

3 | ELECTRICAL PHOTOS

STEPBACK PHOTOS

It is extra important to get stepback photos showing all existing PV wall equipment. Now that there is PV equipment already occupying the space by the utility meter, it could be tricky for the designer to design the wall layout in the event that new PV equipment is needed.

Get a good step back showing several feet on either side of the equipment.
make sure to document any window wells, windows, fences, gas meters, or water lines that are occupying the same wall as this equipment.
- Indicate the location of these obstructions in context.

WIRING

It is important that the designer can see the entire wiring path through the attic, into the PV wall equipment to the Point of Interconnection.

For each enclosure, try to get a photo that shows the sire type/size. See example to the right:

LABELING

The NEC dictates specific labeling needed for PV and other secondary power sources. These stickers will be on each electrical box. Designers will need to see these labels:

get every label on every box

EXISTING POINT OF INTERCONNECTION

Make sure to document how the PV circuit is connected to the residential electrical system.

The examples to the right show the most common types of interconnection:
- Load side breaker (left)
- Supply side tap (right)

For further reading on interconnection equipment, click here.

BATTERIES, NEW GENERATORS, ETC

The full span will be from the eave all the way to the ridge measured along the ceiling joist.

3 | ROOF PHOTOS

SPACE AROUND THE EXISTING ARRAYS

Make sure to take good photos showing the full area occupied by the existing arrays:

make sure to get a few different photos showing where obstructions are in relation to the existing arrays.
In addition, give just as much care and attention to documenting the areas on the roof NOT occupied by PV arrays.

Make sure to do an all new survey of each roof as if this were a brand new residential account:

Photos of EVERY roof section.
Photos of every roof obstruction in context with the rest of the roof.
Photos indicating the current condition of the roof.

CABLE MANAGEMENT

Get photos underneath the existing arrays showing what the cable management looks like:

We're mainly looking for loose cables contacting the roof.

It is uncommon to have loose cables for an existing array that passed inspection in the past, but not impossible. It will result in a failed inspection if not addressed at install.

LOCATION OF JUNCTION BOXES

Make sure that your photos indicate the location of any roof junction box:

This may require you to look around at the array a bit to determine if there are junction boxes hiding under modules somewhere.

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