Can Solar Panels Work in the Dark?

Low Cost Solar Panels That Can See in the Dark

“Well…it can almost see in the dark. Scientists at the Lawrence Berkeley National Laboratory have just announced that they’ve been able to confirm a new high-efficiency solar cell design that handles pretty much the entire solar spectrum. To ice the solar cake, the new technology can be manufactured using ordinary low-cost processes that are currently in use”. Sounds interesting for solar panels and solar cells.

Read The Article Here From Clean Technica

How Solar Panels work

Photovoltaic solar modules are composed of multiple, interconnected solar cells, which effectively trap photon energy between layers of silicon wafers. Negatively charged electrons are then knocked loose form their atoms, allowing them to flow freely through the semiconductors. Separate diodes, and P-N junctions prevent reverse currents and reduce loss of power on partially shaded solar panels.

Since the flow of electrical current is going in one direction, like a battery, the electricity generated is called direct current (DC). Sunlight conversion rates are typically in the 5 to 18 percent range, with some laboratory experiments reaching efficiencies as high as 30 percent. Future possibilities include the development of multi-junction solar cells that are capable of harnessing a wider bandwidth of useable light. We are still considered to be in the “early” stages of solar cells technology.

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Manufactured Stone Damage

Manufactured stone is a lightweight, man-made concrete masonry product that is typically cast into random sizes in a variety of colors and finishes meant to mimic the look of quarried rock. It is generally applied as a masonry veneer to exterior and interior walls, columns and landscape structures.

Manufactured stone, sometimes referred to as precast stone and simulated stone, is technically called adhered manufactured stone masonry veneer (AMSMV). Cultured Stone®, a name that is sometimes used generically, is actually a masonry product manufactured by Owens Corning, and is probably the most popular manufactured stone used in the U.S.

Inspectors are likely to come across manufactured stone during inspections, and will want to be familiar with the details of this building material, as well as some of the problems associated with it. Water damage due to incorrect installation is a significant area of concern, and inspectors and homeowners alike can benefit from knowing how this can occur.

Manufactured Stone vs. Cast Stone

Manufactured stone is often referred to by many different names. While in most instances, the various names can be used interchangeably, manufactured stone is not synonymous with cast stone. Manufactured stone is a different product entirely. Cast stone is a refined architectural concrete building unit whose appearance is meant to simulate quarried stone, but is generally built into a load-bearing masonry wall system. This is a different purpose from the lightweight veneer created with manufactured stone. These two products are manufactured according to different standards and are intended for different applications, although they are often confused with each other.

Pros and Cons

Manufactured stone provides some benefits over quarried rock. However, there are some important concerns to be aware of.

Advantages

Although manufactured stone is basically nothing more complicated than standard cement, the molding and coloring process allows for it to be made almost indistinguishable from real quarried stone. It can be molded and colored to look like a wide variety of different stone facings.
As a lightweight veneer, manufactured stone allows the aesthetic of a real stone structure to be achieved simply and cost-effectively.
Manufactured stone veneer can be applied to wood frame, masonry and metal structures, and does not require foundational support.
When properly installed and maintained, manufactured stone is extremely durable and will last for many years.

Disadvantages

Proper installation is absolutely critical with this product. Incorrect installation of manufactured stone veneer on an exterior wall can lead to serious damage from water penetration, occurring even over a relatively short period of time. There have been reports of serious foundation rotting due to improperly installed veneers in homes less than two years old.
Though the pigment used to color the manufactured stone is generally durable and will not fade, de-icing salts, harsh chemicals, cleaning solvents and paint thinners can cause discoloration and staining.
It has been reported that manufactured stone used around swimming pools can be discolored by chlorine.

Water Damage

Similar to what has become a common problem with synthetic stucco, improper installation of manufactured stone veneer on exterior walls has lead to serious concern about water damage. Improper flashing and drainage details behind the veneer are often the culprit, just like with synthetic stucco, but the damage with manufactured stone can often be more severe. cultured stone house Manufactured Stone Damage This is because, unlike synthetic stucco, manufactured stone is not installed with an air space between the cladding and the framed wall. When the veneer is saturated with water during a rainstorm, it holds rainwater right up against the framed wall. With little drainage or drying space, housewrap (or building paper) and flashing have a harder time diverting the moisture. If care is not taken during installation to cover every detail properly, serious water damage may result under relatively normal weather and seasonal conditions.

Manufactured stone veneers share many similar concerns with synthetic stucco. Proper seams at windows and doors are important, and building paper or housewrap must be lapped correctly in order to keep water diverted from the framed wall. Window pan flashings can be helpful if correctly installed. Bottom terminations of manufactured stone veneer are best equipped with weep screeds of some kind in order to avoid the pooling of water at the lowest points, which can cause those areas to stay continuously wet. The tops of windows and door openings are also spots that will benefit from weep screeds.

Another issue can arise when manufactured stone is paired up with a different material on the same wall. Synthetic stucco, for example, is often installed on part of a wall, with the rest of the wall covered with manufactured stone. Water will penetrate to the wood-frame wall and cause damage if the seam between the two claddings is not properly managed during installation.

Inspection Tips

The most important thing to look for when inspecting an exterior wall clad in manufactured stone is correct installation. Even if there is no visible water damage, steps must be taken to guard against it. Here are some things inspectors can keep in mind when examining these walls.

The base of wood-frame walls need weep screeds, as do the tops of windows and door openings.
In order to avoid water penetration at the seams at windows, doors and adjacent trim, as well as at seams and joints where manufactured stone meets another form of cladding, these seams should be sealed. Corrosion-resistant flashing with a drip edge should be installed with a bedding seal included under the flashing. A water-resistant barrier should lap over the back edge of the flashing for positive drainage. A piece of manufactured stone veneer with an edge that slopes away from the building is also beneficial for use here.
In order to ensure proper drainage and to avoid the possibility of termites tunneling through it, the veneer should not be in contact with the ground or pavement.
The veneer should not be in contact with roofing materials.
If the veneer has been installed correctly, there will be nothing other than mortar visible between the stones.
Kick-out flashings should be installed everywhere they are needed, and should divert water away from the manufactured stone veneer and the building in general. If proper detailing and flashing are not installed, water may penetrate the cladding and cause structural damage from rotting.
The manufacturer’s instructions for the particular AMSMV product installed should always be followed by the installer.

Manufactured stone is growing in popularity, and as inspectors encounter it more frequently, they are also likely to see problems related to water damage. Inspectors who know more about this will be able to answer their clients’ questions and identify potential issues during an inspection.

Dangers of Arc Flashes

Home inspection is one largely unregulated industry whose professionals must nevertheless be aware of their safety and that of their clients at all times. Part of this awareness is being mindful of one’s surroundings, which can be challenging because the “workplace” changes with every appointment. Aside from walking a roof, the electrical portion of a home inspection is arguably the most dangerous. Many things can go wrong in an instant, and some mishaps can be fatal. That’s why, even as generalists, home inspectors should understand what causes electrical shocks and arc flashes so that they can avoid them.

The Basics

The typical electrical service for homes in North America is a 120/240V split-phase system provided by a pole-mounted distribution transformer located at the service drop, which is made up of two 120-volt lines and a neutral line. This triplex cable may include a messenger cable located in the middle of the neutral conductor that provides support over long spans. The neutral line from the pole is connected to an earth ground near the service panel, which is usually a conductive rod driven into the earth. The service drop provides the home with two 120-volt lines of opposite phase, so 240 volts can be obtained by connecting a load between the two 120-volt conductors, while 120-volt loads are connected between either of the two 120-volt lines and the neutral line. The 240-volt circuit is used for a home’s electrical appliances that require substantial power, such as a furnace, water heater, air conditioner, washer and dryer, and oven/range. The 120-volt circuit is used for lighter electrical loads, such as household lighting, and portable appliances and electronics that are plugged into the home’s standard two- or three-prong (with a grounding wire) electrical receptacles or outlets.

Homes in European countries use three-phase power having longer service drops that can serve multiple residences, which is an economical approach to providing power to dense populations in small areas. This type of service drop consists of three phase wires and one grounded neutral wire.

How an Electrical Circuit Works

Everyone should understand that it’s possible to receive an electrical shock whenever electrical power is present, regardless of the level of power or the presence of any protective devices.

An electrical circuit requires a minimum of two wires through which electric current (in the form of electrons) flows. Current is measured in amperes (amps, for short), which travels from a power source (such as the local utility), through the device it operates, called the load, and then back to the source to complete the circuit. In AC or alternating-current wiring, there are about 120 volts in the “hot” or energized wire. This voltage provides the momentum that forces the electrons to flow in the circuit. The power switches on electrical devices are wired on the hot or “live” side of the circuit. The return conductor, known as the neutral, is at 0 volts because it is grounded at the electrical panel. Most 120-volt circuits are wired to deliver 15 or 20 amps of current.

How Injuries Occur

Modern electrical systems are wired with circuit breakers, or with fuses in older construction. These devices serve as over-current protection and are rated in amps. Most household circuits are wired for 15 or 20 amps. Over-current protection devices are designed to protect the electrical system’s wiring and equipment from overheating, but they may not protect a person from electrical shock, which is why any type of component in the system should be approached with caution.

By coming into contact with a live load or energized wire, a person’s body (even a finger) can complete a circuit by connecting the power source with the ground. If this happens, it’s likely that the person will sustain an injury. Most fatal injuries result from high-voltage exposure, but it’s possible to incur a severe injury from low-voltage power if it has a high-current flow. Even if the current isn’t high, a person could be shocked or even electrocuted without ever tripping a circuit breaker or blowing a fuse. Currents of 50 to 100 milliamperes (1 mA = 1/1,000 of 1 amp) can be fatal.

Standards of Practice

The inspector electrical Dangers of Arc Flashes inspector is not required to:

measure or determine the amperage or voltage of the main service equipment;
remove panelboard cabinet covers or dead fronts;
insert any tool, probe or device into the main panelboard, sub-panels, distribution panelboards, or electrical fixtures; or
operate any electrical disconnect or over-current protection devices.

However, many inspectors may choose to go beyond the SOP if they suspect some sort of defect and want to provide fuller information in their reports for their clients.

Warning Signs

Nevertheless, there are warning signs that a panelboard or the system in general may be compromised, and these should persuade the inspector to defer further evaluation to a licensed electrical contractor:

scorch marks on the dead front or the panelboard door, indicating a past or recent arc flash;
rust, which indicates past or recent moisture intrusion;
missing or open breakers that cannot be confirmed to be de-energized;
overloading of the circuits with DIY wiring;
uninsulated wiring;
excessive dust, dirt and debris inside the
panelboard; and/or
any signs of water inside, around or below the panelboard, which can lead to shock or electrocution.

What Is an Arc Flash?

arc flash Dangers of Arc Flashes

An arc flash occurs when a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to neutral or ground. It often happens unexpectedly and can be explosive but brief, or it can last seconds and be rather visually spectacular. It can cause a little damage or it can disable a system and require the replacement of equipment. An arc flash of any size is quite dangerous because its path is unpredictable; it will be attracted to the nearest item with the greatest conductivity, such as an unsuspecting rodent or house pet, or a person. An arc flash can cause a serious electrical burn or even fatal electrocution.

An arc flash can have various catalysts, including:

excess dust;
condensation;
corrosion;
component failure;
faulty system installation;
dropping a metal tool, which may cause even a small spark; and/or
accidental contact.

How Serious Is an Arc Flash?

There are three factors that will determine the severity of an injury caused by an arc flash:

proximity;
temperature; and
the time it takes for the circuit to break.

An injury due to an arc flash can be quite serious because of the violent nature of such a powerful burst of electrical energy. The light from an arc flash can be blinding and disorienting. The heat caused by an arc flash can be as high as 35,000° F, causing serious contact burns, as well as risk of catching fire. It can create a blast pressure of up to 2,000 pounds per square foot, sending damaged and super-heated electrical components flying through the air like shrapnel, with a sound blast as loud as a gun firing (140 decibels). Combine all these unexpected jolts of sensory overload and the physical consequences can be impossible to avoid.

In addition to the inspector being blinded (temporarily or permanently) and/or severely burned, another result of an arc flash is that it can set electrical components on fire, and the proximity of the inspector means that s/he’ll likely inhale toxic vapors, which can cause respiratory and neurological damage, depending on the duration of exposure. Also, the force of the shockwave can rupture eardrums. Furthermore, being shocked by a current above 75 mA can cause the inspector’s heart to go into a state of ventricular fibrillation, which causes it to beat irregularly and rapidly without pumping any blood. If this condition doesn’t quickly normalize, either by itself, using CPR, or with the aid of a defibrillator, it may lead to a heart attack, which can be fatal. If the brain is deprived of oxygen for more than three minutes as a result, this, too, can be fatal, or it can land the inspector in a vegetative state.

It’s not uncommon for an inspector to never fully recover his previous quality of life after experiencing an injury from an arc flash.

Precautions for Inspectors

1. Assess your risk tolerance. You are not required to perform an invasive electrical inspection. Removing the dead front of the electrical panelboard exceeds InterNACHI’s SOP. Unless you are highly confident of your technical training, as well as the situation, and you can also confirm that the system is de-energized, any suspected problems that require an invasive inspection should be disclaimed and deferred to a licensed electrical contractor.

2. Wear PPE.

Regardless of whether you choose to exceed the SOP, always have available and wear the appropriate PPE, including fire-resistant clothing and insulated gloves made specifically for working with electrical equipment. It’s also wise to use protective eyewear. Even a small spark can cause a severe eye injury.

3. Check your surroundings.

If there is a lack of ground-fault circuit interrupters (GFCIs), or if there is evidence of a water leak or moisture intrusion, or if the panelboard has scorch marks, potentially indicating a previous arc flash or electrical fire, pay attention to these and other clues, as they may lead you to immediately defer the electrical portion of your home inspection. Again, assess the risk and then decide whether to proceed.

4.Use the appropriate tools.

According to 3.7.I.I. of InterNACHI’s SOP, inspectors are required to:…test all ground-fault circuit interrupter receptacles and circuit breakers observed and deemed to be GFCIs using a GFCI tester, where possible…

Make sure your tester is working properly before your inspection appointment. An infrared camera is also an excellent tool for detecting hot spots during the electrical inspection.

stay back stop sign Dangers of Arc Flashes 5. Protect your clients.

Many inspectors encourage their clients to accompany them during the inspection so that they can point out important shutoff valves and switches, and discuss maintenance items. However, inspectors should use extreme caution when deciding whether to have the client with them during inspection of the panelboard if signs indicate that it may not be safe. This is true for any area of the home that exhibits signs of instability or some apparent hazard.

Arc flashes are just one of the more serious examples of what can go wrong during an inspection, which is why inspectors should follow their training, as well as their instincts, and protect themselves and their clients on the job. It’s always better to be safe than sorry and incur a grievous injury, which can put both your livelihood and life at risk.

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