Engineers say an emergency cutoff switch is a redundant feature on inverter-equipped solar arrays. (Photo by mjmonty)

Engineers say an emergency cutoff switch is a redundant feature on inverter-equipped solar arrays. (Photo by mjmonty)

Iowa bill would require debatable safety feature on home solar

An Iowa bill requiring a safety feature that some engineers say is unnecessary has critics questioning whether the legislation is an attempt to stifle distributed generation.

The legislation, SF 406, would require customer-generators to install an external disconnection device. The device itself would add a few hundred dollars or more to the cost of a solar array or other system, but the bill also would impose daily fines of between $1,000 and $5,000 for any energy generator without one.

The requirement would apply to existing systems as well as new ones, according to state Sen. Tony Bisignano, who introduced the legislation.

Clean-energy advocates in the state have been focused on defeating the bill, which they see as an effort to discourage rooftop solar installations, in particular, by piling on an additional – and needless – cost.

“This is something that’s coming from the utility behemoths through the IBEW (International Brotherhood of Electrical Workers),” said Barry Shear, the president and owner of Eagle Point Solar in Dubuque. “They’re the ones pushing this.”

“It’s a well-designed play to talk safety, but it’s really designed to be a barrier to solar,” said Josh Mandelbaum, a staff attorney in Des Moines with the Environmental Law & Policy Center.

Mandelbaum questions why the union didn’t raise concerns about the issue when it submitted comments to the Iowa Utilities Board on distributed generation last year.

“This is exactly the type of issue that would have been appropriate to raise at that time,” Mandelbaum said, “and they were silent. That, to me, suggests that something else is at play.”

‘Create some uniformity’

Bisignano said he introduced the bill to ensure the safety of utility workers making repairs in the event of a power outage. He said repair workers must be assured in such a scenario that no power is coming into the grid from distributed generators, and the only way to be certain of that is for the linemen to manually disconnect any solar panels in the affected area.

Michael Coddington, a senior electrical engineering researcher for the National Renewable Energy Laboratory, doesn’t buy it.

“It’s just….an effort to create barriers to deploying PV,” he said. “When I see these rules enacted, it’s clear the devices won’t be used, and will add cost.”

Bisignano maintains that he “would not want to discourage any alternative renewable energy. That would not be my intention by any means. This bill would ensure that there is no opportunity for energy personnel or electrical workers to be electrocuted. That’s the long and short of why I filed the bill.”

In fact, Iowa’s two major investor-owned utilities, MidAmerican Energy and Alliant, and nearly all of the state’s rural electric co-ops already require their customers to install external disconnect switches. Currently, Iowa leaves requiring the devices at utilities’ discretion.

So why would they support a bill mandating a device they’ve already chosen to require?

Alliant spokesman Justin Foss says the bill “is not about requiring the disconnect. It’s about requiring the uniform placement of the switch.”

Utility linemen and other possibly other electricians looking for these switches need to know where they are, he said. Hence, the need for consistency in their location. The bill does state in some detail where the switches should be placed.

“Our hope with this bill is that we could create some uniformity on the grid,” Foss said. “While there are many different utilities, there is one grid.

‘Completely unnecessary’

But wherever the switch is installed, it’s still redundant and unnecessary, according to a 2008 study done by the National Renewable Energy Laboratory.

Coddington, one of the study’s authors, argued in the paper that there are at least a half-dozen procedures and technologies, now in effect, that prevent power from a small solar array from backfeeding onto a grid – and electrocuting someone in the process.

Rooftop solar panels have inverters, devices that change direct current to alternating current. They only send power out to the grid when they sense power coming from the grid, Coddington said, meaning that when an outage occurs, a home solar system cannot send power out to the grid. Sending a utility worker to shut off a disconnect switch is simply redundant, he said.

It’s also time-consuming, he pointed out, at a time when utilities are under pressure to restore power as quickly as possible.

Eagle Point’s Barry Shear concurred, saying, “From a technical standpoint, it’s completely unnecessary.”

Coddington pointed out that standard safety protocol requires utility workers to assume all electrical systems are carrying power, and to dress and use tools that would insulate them from live wires. Utility workers who follow standard procedures would not have a problem, he said, even in the highly unlikely event that a solar system was feeding power back to a grid experiencing a power outage.

While Iowa is considering adopting an external-disconnector requirement, the NREL report documents a move away from that in other states. As of 2008, utility regulators in eight states had eliminated their EDS requirement. Another nine states had decided to allow utilities to make their own decisions in the matter.

In solar-heavy California, two large utilities dropped their requirement that solar arrays have external disconnect switches.

The reason, according to Coddington: “People started asking them the hard questions.”

The ELPC is a member of RE-AMP, which publishes Midwest Energy News.

9 thoughts on “Iowa bill would require debatable safety feature on home solar

  1. An external disconnect is an excellent safety device. Just do it and quit whining. The results of not doing it could cause a costly and unsafe condition. You harm someone and see what the costs would be! It is good business to use all the safety devices that are available. A few hundred dollars of upfront costs for a safety switch is A-OK.

  2. I work for a utility, and see those line-service men and women who are missing hands and arms, because of an encounter with distribution electricity. For those folks, a loss of concentration, or a simple distraction is serious – you make a mistake on a high voltage system, and you will get burned – you may lose a body part, or even die by electrocution.

    In question is an electric disconnect switch, at a standard location (just as is required for your outdoor air conditioning unit). If an animal or storm takes down the power, you want it restored quickly – our service people are dedicated to doing that. How will they know if a distribution line is being back-fed by someone’s solar array up on a roof? The answer is having a standard that includes a disconnect switch at a prescribed location, for any alternative generation source.

    It’s not some anti-solar maneuvering by the big, bad utility, it’s just common sense, safety. Let’s encourage renewable energy, but don’t compromise on homeowner and service worker safety.

  3. Most external equipment has an EXTERNAL disconnect…..for example your Air Conditioner. It’s located within 6′ of the equipment with a liquidtight power feed. The Midwestern Electric Ducks out of Mankato MN are very popular for this.

    Are we saying that because there is DC there is no need for an external disconnect? Sounds to me if a homeowner is trying to retrieve a Frisbee from under\around the equipment they’d be safer with an external disconnect…..

  4. Anyone who has worked in an industrial environment knows that you never trust “engineered” safety systems to protect workers. Solid state switching devices can fail, and embedded software in the shutdown circuit can have flawed code. The only failsafe way to prevent a backfeed into the utility system is to have a visible (and lockable) disconnect switch. It is true that utility wokers have to assume that a circuit is hot unless it is visibly grounded and must use the appropriate personal protective equipment (PPE). However, the use of PPE is not a substitute for eliminating the hazard altogether when possible.

    Bottom line: It seems to me that if the relatively small cost of a disconnect switch discourages someone from installing a PV system, the system probably didn’t make sense from an economic standpoint anyway.

  5. A’m an electrical engineer and my point of view is that any system producing electricity should have a main disconnect switch. It is not to push the owner to spend more money, but for his own safety.

  6. The Iowa Solar Energy Trade Association is opposed to a disconnect. This law requires a 2nd disconnect next to the meter and in some cases in addition to the service disconnect that already exists at the meter. This would require a separate wire run in some installations all the way back to the meter. Cost overrun that the customer has to recover. Read the first draft of this bill and you will see it had nothing to do with safety and a lot to do with running up the cost of an installation.

  7. Solar inverters have a build it DC disconnect. Then there is a branch circuit breaker or fused disconnect that can turn it off that have to be within site of it. If it’s a branch circuit breaker, then there’s a main breaker on the same panel that can turn it off typicaly. Then when you go to the main service, there is either a fused disconnect, pole top disconnect, or main breaker that would kill the solar. This legislation would add one more disconnect to this. If this was about safety they’d be looking at standby generators that people hookup improperly and are signficantly more dangerous. As far as line injuries go, they are almost always caused from not following safety procedures.

  8. I’ve had solar on my roof for 4 years now. Our local utility mandated such a switch at the time of install. We’ve been through multiple blackouts since then, and not once have I, the utility, an electrician, or anyone else ever moved that switch to the “off” position.

  9. I’m a solar owner in Iowa – installed a system last winter. My utility already requires me to install a labeled disconnect where the solar enters the house. I just counted the number of disconnects I’m required to have. There is one at the solar panels, there is one next to the meter, and one in the basement in the breaker panel. On top of that, my inverters must have power to give it. They don’t work if I don’t have power and take over 15 minutes to come back on line after the power is restored to my house. The utility required this type of inverter and I had to provide documentation and labels to prove it and submit to an inspection. I think we can call it safe already.
    Now I’m looking at having to move the disconnect (it is not placed where the new law says it is required to be). By reading the bill it looks like I will also be responsible for contacting the fire department to let them know I’m using the sun to provide my family electricity.
    If only the utilities own lines were so safe! My next door neighbor is a former lineman and he is shaking his head. This is outrageous. The utility ran me through the wringer to get this system installed. Enough is enough, its pretty obvious what’s going on here. BTW, the politician that authored the bill does not like solar.