How will the Solar Roof pass regional fire / building codes?

How will the Solar Roof pass regional fire / building codes?

In my area, the wiring for solar must be run in metal conduit on the exterior of the roof so that firefighters can avoid cutting energized wiring. The roof surface cannot be completely be covered by solar panels either to allow firefighters access to fight attic fires. In attached homes, three feet of roof on either edge cannot contain solar panels. As beautiful as the Solar Roof is how would a firefighter know which tiles were energized and which ones were dummy tiles when cutting through the roof? How would they even know the house has a Solar Roof at all since it looks no different than a standard roof.

Since each county, and in some cases each building inspector, determines what is allowed and what is not, I see a lot of debate between Solar Roof installers and the local building inspectors.


JAnnen | 30 octobre 2016

Thanks for starting this tread. The details seem troubling.

Efontana | 30 octobre 2016

dead tiles can be more visible when viewed by a fire fighter.
dead tiles can be placed according to code.
arrays can be defined as vertical stripes with both terminals at the gutter. conduit is lower edge of roof.

JeffreyR | 30 octobre 2016

Good points for sure. Remember the types of tiles these are replacing would be pretty difficult to cut through already. I imagine slate or terra cotta tiles were pried out of the way w/ a crowbar. Same technique would work for tempered glass.

EaglesPDX | 30 octobre 2016

@Frank.B.Smith " The roof surface cannot be completely be covered by solar panels either to allow firefighters access to fight attic fires. In attached homes, three feet of roof on either edge cannot contain solar panels."

The reason for the regulations was because the solar panels sat on the roof, impeding access. In the case of glass tiled shingles, no different than a slate or terra cotta roof, fire man has to bash it in to access the attic.

The roof being energized and presenting a electrocution or even shock risk are zero. This is very low voltage current and in a fire there's not going to be any power generated at all.

Is glass a valid roofing material is the question and I think it is. Fireman should like it since it is not flammable like asphalt shingle roofs.

Sudre_ | 30 octobre 2016

Good topic Frank.

Like Efontana stated above they can install non-solar tiles that look the same from the ground to provide the code spacing. It seems watching the video that when looking at the tiles up close you can tell which ones have the solar panel in them and which ones do not.

The exposed conduit thing to me has always been odd. I can run pipe anywhere I want in a crawl space or attic for any product except solar as long as the power runs are 2"s (or more) below the actual roof (in St. Louis). For example I can run a pipe run to an exhaust fan below the roof by 2"s or more then run up into the bottom of the exhaust fan for the connection. That would not be aloud with solar. I think what would help is some kind of shutoff in the panel so the panel itself would not generate power unless it was receiving a signal from the inverter. If the inverter has no power obliviously the panel would not be on either because it would not be receiving a signal. The signal could be sent over the 24volt connection between the inverter and the panel. Kind of like how a Powerhouse X10 system turns off individual outlets at the plug itself.

The fireman could know the house has solar because they could get the 5 minutes of training (along with all the other training they get) that tells them to check for a disconnect switch by the electric meter. My traditional solar system has stickers at the meter where the disconnect is for the solar. My solar shuts down when power is lost to the house. If the firefighters turn off my house there are no live conduit runs anywhere. If I had a free standing solar system with no utility connection a disconnect could still be mounted outside for the firefighters to shut everything down.

I do find most fire marshals will listen to reason. They just want their men and women safe.

EaglesPDX | 30 octobre 2016

@Sudre "Like Efontana stated above they can install non-solar tiles that look the same from the ground to provide the code spacing."

The code spacing is based on solar panels that sit on top of the roof.

In this case the glass tiles are the roof. That the tiles have imbedded PV should not be an issue. Glass tiles being fire resistant should get looked on favorably especially in fire prone areas.

Taking an ax to the glass tiles presents no electric shock risk. | 30 octobre 2016

Not sure I agree about the risk. It really depends how the cells are connected. Each cell produces a fairly low voltage. The risk comes when hundreds are connected in series. At a portion of a long string you could have hundreds of volts. Tesla may not use this configuration so it may be a non-issue. For example, they may only connect enough to generate a maximum of 24v, in which case it would be safe to cut anywhere into the solar tiles.

A disconnect on typical 2x4 panels today with a single inverter does not turn off the voltage at the panels - they are still live and producing possibly leathal voltages. It only disconnects the inverter from the AC to protect linesmen when the city power is out. This kinds of system are legal today, but must be clearly marked.

Now many systems use microinverters - these are one per panel and disconnect at the microinverter. The panel itself is still producing voltage, but usually only 12-24 volts, which is rather safe. They are never connected in series. | 30 octobre 2016

I should also point out there are a number of embedded solar roofs over the last 12-15 years. We have a group of houses nearby with Kyocera tiles that were built in 2005. The SolarCity/Tesla tiles look a lot better and seem to have more flexibility in installation.

For those that want to see all the differnt kinds of tiles:

EaglesPDX | 30 octobre 2016 "Now many systems use microinverters - these are one per panel and disconnect at the microinverter. "

Pretty sure the Tesla roof does based on the use of SolarEdge.

up north | 30 octobre 2016

They can set electric panel up to turn off 220 power and solar when smoke detectors go off. And firefighters wont cut holes in the roof at a designated spot. They cut holes exactlly where needed. Outlet electric would still work.

SUN 2 DRV | 30 octobre 2016

Does anyone know if the solar roofs on display at the intro were actually wired up and operational? Or were they just glass tiles attached to the roof but left unconnected?

KP in NPT | 30 octobre 2016

I read they were not connected/operational. I don't remember where. I'll see if I can find it.

KP in NPT | 30 octobre 2016

This article states they were "non operational" -

as does this one:

I can't find the original article that I had read before, that said they were non operational and that Tesla spent 2 weeks installing them on the set homes.

Ross1 | 30 octobre 2016
kaffine | 30 octobre 2016

Unless the fire happens at night the solar panels can still put out power. Anything over 35V is considered a shock hazard in a wet location . Solar panels setup for 24V can have OC voltages that exceed 35V so either have to keep the panels setup for 12V or go with disconnects. I know they make combiner boxes that can kill power from the panels then only the wiring between the panel itself and the combiner box is energized and if the panels are 12V that keeps the voltage at safe levels.

Firefighters are likely to cut through the roof with a power saw so glass tiles are not likely to be an issue. May see a slight change in the blades they use. Hence the reason they don't want power right under the roof as the power saw will cut through it as well. And with PV arrays they don't trip breakers when cut so the wire can remain energized and start another fire and or pose a shock hazard.

Solar panels have an issue as they don't typically trip circuit breakers on short circuits. There are ways they can disconnect each panel but I haven't seen panels setup with that and it would require extra wiring. Would need a relay on the output that is energized by a control wire.

Not likely to see automatic power disconnects for fire alarms in residential. Too many false alarms and most houses don't have emergency lighting so now if it is a fire you have to evacuate in the dark. Code now requires marked disconnects to kill power if multiple disconnects it must be indicated and both marked. Of course not all places have adopted the newest NEC code yet.

Ross1 | 30 octobre 2016

No amount of volts can hurt you, it is amps that kill.

codyb12889 | 31 octobre 2016

I took some time to read up on this just for my local area and could not find anything conclusive as everything pertains to actual panels.

My current THEORY is that since the panels are interconnected and not actually running a high voltage line like traditional panels it seems to fall in a bit of a grey area. With that being said I think this topic opens the "can of worms" that could hurt the moving forward of this technology.

@Frank.B.Smith thanks for bringing this up, you have likely brought up something that there will be a good bit of "legislation" on in the next year or two. It will be a very interesting question to see answered over time.

mikblyth | 31 octobre 2016

I cannot see a problem really, they will do the same to what they do to the cars, there is an area in the frunk that tells the emergency services how and where to disable the power.

KP in NPT | 31 octobre 2016

If they expect installation to begin this summer, I'd think they have the building code thing pretty close to sorted.

syd | 31 octobre 2016

They might, but the municipalities don't. To them Solar is Solar and all the solar panel codes will apply. The first few years of this is going to be the issue. Building code departments move slowly. It took years to adopt the codes for the 3', conduits, etc. It's going to take a while to adapt and allow for solar roofs.

firedawgbw1 | 31 octobre 2016

As a firefighter, a few concerns came to mind as well. A. Something to indicate the house had this type of roof and power box. B. How to secure the power to the power box. C. How the glass roof affected the temp of the fire. D. Ventilating the roof E. Safety of standing on the roof to ventilate. It would be helpful if Tesla came up with some type of packet of information to aid in fire department training for these like they do with the cars.

JeffreyR | 31 octobre 2016

I expect Tesla to produce training videos like they did for the cars.

Rocky_H | 31 octobre 2016

@Ross, What the heck is "W = Ei"? Is that the terminology from 50+ years ago or something? I do think I recall seeing E representing "electromotive force", which is voltage, but I don't think I've seen W as representing power in the equations, although I guess that is "wattage"?

I learned the two equations as
V = IR
P = IV

codyb12889 | 31 octobre 2016


What would be adequate in your opinion for indicating that a house has a solar roof? I think putting up a sign of some sort is something people would do voluntarily for both safety and for a bit of showing off.

I am imagining something similar to the ADT yard signs but feel like that would easily get over looked.

SUN 2 DRV | 31 octobre 2016

The system design and interconnect facilities are the most interesting part to me, and they seem to be currently unanswered.

People are guessing it might be a low voltage system with lots of the tiles connected in parallel. But that would be impractical except for the smallest systems since the required aggregated currents would correspondingly go up as would the conductor sizes and weights. All of that leads to higher losses. Hence why typical solar installations are at least 240 V AC (microinverters) up to 600-1000 V DC (Central inverters).

And since each roof tile will need to be connected at time of installation that's a huge opportinity for hundreds more loose connections compared with a panel based approach. So a KEY factor is evaluating how well Solar City as addressed the tile interconnection issues.

Rolando Dominguez | 31 octobre 2016

I would be willing to do this if my ROI is around 7 years or so. How do you justify a roof that is only 10-15 years (I'm at 13 Yrs) old which is probably not even 50% through it's life span and having this installed? Would it be installed on top of the existing roof shingles? There are so many variables that go into deciding to move forward that I don't know where to start... Feeling overwhelmed but want to get Solar to feed my house and Tesla charging needs.

Does anyone know what size system makes sense if your looking to support a 4,000 sq. foot house with an in ground pool (Looking to add a heater next year), Jacuzzi, 2 zone AC Unit, Tesla Model S

Ross1 | 31 octobre 2016

All these should be posted in the Vaporware and Concepts thread

kaffine | 31 octobre 2016


Industry standard is it only takes 50mA to kill someone. There have been cases where as little as 15mA has caused fatalities. So while it may be the current that kills it requires very little current. It still requires enough voltage to overcome the skins resistance. Code says anything over 35V in wet locations is a shock hazard however under the right conditions it can be much lower voltage. They had to draw the line somewhere and under most conditions under 35V is touch safe,

And it should be P=EI


In formulas they normally use E=IR or P=IE

E = electromotive force measured in Volts

I = Intensity measured in Amps

R = Resistance measured in ohms

P = Power measured in Watts

Ross1 | 1 novembre 2016

I used a small i for clarity so it didnt look like L or 1.

W=EI was as said, over 50 yrs ago, but hey, I guess physics laws dont change | 1 novembre 2016

@Rolando - It's complex to figure out what is best. You should get a few solar install estimates. It varies a lot by location (amount and angle of sun), your house roof position, your city (various laws), and how much power you uses (a year's worth of prior bills is handy).

The Tesla solar tiles are intended for new construction or someone who is having the roof replaced. I doubt it is practical, cost wise, to use it on top of an existing roof, and it may not be allowed without the existing roof removal, as there are lots of building codes on how roofs are installed. City codes often frown on roofs on top of roofs (although some places allow it).

McLary | 1 novembre 2016

Interconnections and operating voltage are huge issues. Many more questions than answers.

vperl | 1 novembre 2016

I am sure Tesla and Solar city never got approval from all authorities to use these tiles.

Whoops, fail

Yep, Tesla is so uneducated they forgot to get proper building codes and NEC codes .

Yep.... Whoops. Fail.

brando | 3 novembre 2016

OMG, seems vperl been taken over by demons. Sorry, an inside joke, if this post makes no sense, your fine, just read on.

PS- Tesla is NOT the first company to introduce new building products, even on roofs. Which is what vperl is driving at. But as McLary would say "can't we wait, till they are approved in all the US, states, counties and metro areas?" Believe it nor not. You have to run, for example, the exact same UL fire rating test over and over and over again so many local governments (and their approved labs) can collect fees. Yeah, had to do that for a startup urethane insulation board manufacturer. You might think we were the first? OH, no. We were only one of dozens of urethane board manufacturers. DOW supplied us all. What a racket government so easily develops into.

Sorry. I didn't mean read on with my post. I meant to imply you could skip mine and read on.