The Benefits of Achieving NABCEP Certification

Overall, the benefits of NABCEP certifications are to the industries they serve. The North American Board of Certified Energy Practitioners (NABCEP) was founded in 2002 as a 501(c)(6) non-profit organization with the stated goal to develop voluntary national credentialing programs that will promote renewable energy, provide value to practitioners, promote worker safety and skill, and consumer confidence in the industry. But how does certification help your career? Consumers need to be confident of their choices.

Consumers at all levels need to know as much as possible about the products they purchase. However, it’s next to impossible to know all that is necessary to make the best choice, so they depend on third-party grading and rating systems to help make decisions. This works out very well for the consumer if the grading/rating organization is doing the hard work of vetting the products and services provided, like NABCEP.

But it also works out very well for the product/service provider. This is especially true when it comes to certifications held by installation contractors. A certified installer’s high standards and achievements stand out so the consumer can see there is a quality difference with minimal research. NABCEP has done a great job of serving the solar industry by providing this credentialing and certification process and standard. They now offer several levels of credentials and certification.

The entry level NABCEP certification is the Associate Credential; the requirement to sit for this exam is to complete a solar PV course from a NABCEP approved training provider and then pay the registration fee through that provider. Achieving this NABCEP Credential provides the holder with more visibility in the industry to employers and potential customers. The credential holder’s name is placed on the NABCEP web page under NABCEP Associate Directory.

The highest level of certification is the NABCEP Certified PV Installation Professional. The minimum education requirements to sit for the exam are 58 hours of solar training with 40 of those hours being advanced level, solar PV specific, provided by an accredited school. A minimum 10-hour OSHA card is also required. Verifiable experience in PV design or installation is also required to sit for the exam. The value of this certification has many benefits in the solar industry and is often required by entities such as utilities or governments. Many developers will specify and require that the solar contractor must have this level of certification. Showing potential customers that you are a certified solar contractor will give you the advantage over a contractor who is not certified. The certification holder’s name is placed on the NABCEP web page under Certified Locator.

For professional sales people, the achievement is the NABCEP PV Technical Sales Certification. The education requirement varies widely from 0 to 60 hours of solar training depending on the person’s background. However, it would be a good idea to take some training courses to prepare for the exam. The first person a customer meets is usually the sales representative; if the sales person is certified, it provides the customer with confidence and an element of trust, elements that are an essential part of winning an installation contract.

NABCEP now has three Specialist Certifications: PV Installer Specialist, PV Design Specialist and PV Commissioning and Maintenance Specialist. Each of these require 24 hours of advanced training from an accredited school. Verifiable experience in each of these specialist categories is also required to sit for the exam. A minimum 10-hour OSHA card is also required. Each of these certifications is focused on the individual’s specific area of expertise. The greatest value to the individual holding the specialist certification is companies who employee certified specialists gain a level confidence with this individual and it also improves the company image to the potential customer.

Another level of certification is directed to building inspectors. Many of the building inspections are now contracted to professional inspectors. These inspectors are usually certified in as many fields of building construction as possible. The NABCEP Certified PV Inspector certification provides these inspectors with this credential that indicates they possess a sufficient level of knowledge and expertise with PV system inspection requirements. No training or experience is required to sit for this exam. However, it is highly recommended to sufficiently educate yourself prior to registering for the exam; it requires extensive knowledge of the IBC, NEC and PV system design.

Certifications are key to any industry’s growth and success. The solar industry is still young and it cannot afford failures due to poor quality installations. One effective way to guard against these failures is to support industry certifications. NABCEP has done a great job of providing their widely accepted certification program to many from different backgrounds. When you become certified at any level, you enhance your opportunities for personal success, you help raise the standards of the industry and you help provide consumers with the ability to make smart choices.

Solairgen PV specific training programs are NABCEP approved and IREC accredited solar PV training programs, designed in support of industry certification and professional excellence.

Kelly Provence
Solairgen School of Solar Technology
IREC Certified Master PV Trainer
NABCEP Certified PV Installation Professional
NABCEP Certified Technical Sales Professional
Master Electrician

Logo for Certified Master PV Trainer Kelly Provence Solairgen IREC Accredited Training Provider Logo  NABCEP Installer Logo   PV Tech Sales Cert Logo

Managing PV Wire

Solving the Problem of PV Array Wire (or Cable) Management

Wires covered with wireThis is the one part of installing a PV array that never seems to get easier although racking manufacturers are doing their best to help. There are three objectives to managing these PV cables: 1. Secure them in a manner that is code compliant.  2. Protect the cables from damage. 3. Minimize visibility or secure them attractively. The objective is to select a method that does all three with minimum effort and cost.

Let’s start with #1. The NEC states that USE-2 (PV wire/cable) must be secured within 12” of a junction box and then every 48” of length. While it is easy to achieve the 48” support requirement, it is not as easy to meet the 12” of a junction box requirement, especially from the PV module junction box. This requirement is often overlooked by inspectors if the cables appear to be well secured. The picture below shows how this 12” requirement is achieved and how it is not.

12 inch cable

Secured within 12” with cable clips

18 inch zipties

Secured 18” with zip-ties to rails

Another code requirement is the minimum bending radius of USE-2 and listed PV wire. USE-2 has a minimum radius of 5x the diameter of the cable; that is about the curve of a large cup. PV wire usually requires a radius of 8x the diameter of the wire; that is about the curve radius of a good hamburger.The problem with zip ties is with their strength and usage rating. The typical black zip tie may not have a sufficient rating for the lifetime of the PV module.

There is also an NEC requirement for the work to be in a “neat and workmanlike manner”. This gives the inspector a lot of leeway. Chances are good that if an electrical installation is sloppy, it also has some installation errors.

For ground mounted PV arrays, protecting PV conductors from unauthorized personnel is also required. This can be done with a fence, adequate height (8’ minimum) of the cables above ground or a type of screen fastened to the PV array modules. (see images on next page)

Wires covered with wire   Larger panel wire covered with wire

By protecting the cables from unauthorized access, they are also easier to secure.

Code compliance usually addresses #2 and #3 objectives. The best way to meet these objectives is to use the racking manufacturer’s wire management system and supplement it with some generic products like wire clips that attach to the module frame and UV rated zip ties. Pictured below are two manufacturer designed products and features for wire management.

SnapNRack photo

SnapNrack uses their open rail system for wire management.
The plastic clips secure the cables into the rail trough.

ironRidge photo

IronRidge provides cable management clips that are secured into the top rail.

It is always a good idea to use the most common PV module frame mounted cable clips as a supplemental wire management system. One wire management system is never fully adequate for the various conditions that occur on site.

When using zip ties to supplement the wire management system, consider the life of the plastic tie. It needs to be UV and hard-use rated.

UV photo

The primary problem with wire management comes from lack of planning. By simply visualizing how wire management is to be handled prior to starting the job will go a long way toward making it a simpler process instead of a source of aggravation.


Kelly Provence


The Importance of Optimum PV Array Size for Solar PV Systems

Residential Solar PV Ground Mount SystemThe question of optimum PV array size is the first question to be answered when designing the PV system. There are several factors that have to be considered to arrive at the best size. The customer budget, the available area for the array and the purpose of the PV array are always primary considerations. The budget is usually the most flexible since the system can be financed. The second may be difficult to get around if the location options are limited and restrictive. The third part is where most mistakes are made. There are generally two types of systems, (1) stand-alone and (2) utility grid interactive.

The stand-alone system must be designed to serve the electrical loads throughout the year. The PV array is usually sized to serve the loads in the month with the highest ratio of electrical load demand verses available solar energy. As long as the electrical load demand is known and the solar resource is known, the calculation is made for each month of the year (Avg. daily loads kWh ÷ Avg daily insolation ÷ Power conversion efficiency % = ratio) The ratio is the exact size of the PV array necessary to offset 100% of the energy consumed in that critical design month. The hard part is usually determining the kWh of electrical consumption.

The stand-alone system can be off-grid with generator backup or grid supported. If it is grid supported a portion of the house electrical loads are served by the stand-alone system. The PV array is sized for the stand-alone portion of the house.

The graph below show a typical PV system output capacity compared to the electrical consumption for each month of the year. The PV array is exaggerated in size to cover the worst ratio months of the year.

Graph 1

Grid interactive systems must consider how much power can be fed into the electrical system and remain compliant with the utility interconnection agreement and the best power offset value. The most common interconnection agreement is Net Metering for the billing cycle. It is typically set to offset up to 100% of consumption with solar PV generation during the monthly billing cycle. Energy generation in excess of 100% is usually compensated at avoided cost, about 1/3rd the rate of retail. The obvious objective here is to not generate more than is consumed for each month of the year. The challenge is to project generation and compare it to consumption throughout the year.

The months that usually control the PV array size are in the spring and fall. We consume less energy during these periods because of the reduced need for heating and cooling. Coincidentally, these are usually the best two periods for solar PV generation because of clear skies and lower temperatures, April and May are typically the best generation months.

The graph below shows the typical electrical usage for residential customers. The PV system that is designed to offset 60% of the annual electrical consumption is generating 100% of that consumption during the month of April.

Graph 2

A third type of system is a self-consumption type system that requires energy storage and is designed to connect to the grid but not sell into the grid. The PV array size usually follows the same rules as the interactive guideline above, but it can be more complicated and requires a smart control system with consumption and generation metering to keep everything in check.

It is OK to oversize a stand-alone system but with interactive systems keep an eye on the low-consumption vs. high generation months.

Kelly Provence


Solar Shingle

The Future of Solar PV Shingles

Solar shingles seem like the most logical application for the future of solar PV systems, serving two purposes – a roof and a solar PV system – by simply integrating the shingles into photovoltaic roofing. There are problems with the solar shingle system, slowing its mainstream marketability, but may work if the following obstacles can be overcome:

(1) The cost of solar shingles is not competitive with conventional solar electric PV modules. Costs might balance with high penetration into the photovoltaic industry, but that takes time.

(2) The physical constraints of solar electric roofing shingles do not allow for custom fitting to varying roof dimensions. This is an obstacle that is difficult and expensive to overcome.

(3) The solar roofing contractor’s training is limited to the narrow market of solar shingle manufacturers. The manufacturers will not train contractors in areas where sales are not profitable, so the solar shingle market restricts customers’ choices and is controlled exclusively by the manufacturer.

(4) Roof warranties can only be fulfilled by the solar roofing manufacturer and its own factory-trained solar roofers. Repairs may be delayed if there is not a trained contractor in the customer’s area. Roof damage not covered by the solar roofing manufacturer would be difficult or impossible to have repaired by conventional roofers who are not trained to work with solar shingles.

I would like to see this product succeed in the market, but no manufacturer has made a successful long-term run with residential solar roofing to date, and some who are attempting it have yet to make a profit in the photovoltaic industry.

Mainstream success of solar shingle roofing may happen, but it doesn’t appear to be coming in the near future.


Kelly Provence
NABCEP Certified Professional PV Installer
IREC Certified Master PV Trainer
Solairgen, Inc.

Image of a Poor Solar PV Installation

How to Prevent a Substandard Solar PV Installation

No one wants a poor PV system installation, but it happens from time to time. The good news is it’s 100% preventable but you should first understand the causes of a bad installation, and then learn how to prevent it. We tell you how.

Problem #1: The installer is unskilled and unknowledgeable about the correct installation process, but how do you determine that?

Solution: Screen the installer. Ask for references and evidence of their experience such as pictures, invoices, permits and inspection reports.  Ask how much training they received, and where they received it. You can even ask to see their graduation certificates. Inquire about industry certifications (NABCEP) and whether they have a contractor’s license.

If they can’t or won’t provide any of the above information, don’t contract with them no matter what they promise you. A reputable installer will be eager to provide their credentials.

Problem #2: A skilled and experienced installer wants to install a brand-new product that is not fully understood or tested in the industry. It is not uncommon in this industry for changes in PV products to outpace the contractor’s full understanding of them. Don’t be the guinea pig.

Solution: Insist on tried-and-true system components unless it’s just an improvement over a product that has been around a while. It’s best to see how those brand new products hold up during beta testing. Find out by going to the internet and doing some independent research. Don’t be afraid to tell your installer what you learned and that you prefer another product.

Problem #3: The contract price is too low for the contractor to make a profit. Incorrect bidding is common when a contractor is inexperienced, but underbidding occurs occasionally even for experienced installers.

Solution: It is best to find out the going price for the installation prior to accepting a bid. If you don’t know the going price, get more than one bid and then compare. Most companies will give you a generic bid without a problem.

Some Advice: If the installer you select has underbid the installation, it may save you money in the long run to offer a fair, renegotiated price. Some contractors are very honorable and will do the same good job even if they lose money, but some will not and that may cost you more down the road. And remember, a deal too good to be true is usually exactly that, untrue.

In summary, the real responsibility is on you, the customer. Take a day or two to learn about the PV products, the installation process and who the good contractors are. There are many organizations out there to help you. Here are a few links to get you started: American Solar Energy Society, Solar Energy Industries Association, NABCEP, IREC, and The Solar Foundation.

Finding skilled, experienced solar PV installers isn’t difficult, and eliminates the frustrating and very expensive future problems of a bad, or failed, solar PV installation.

Kelly Provence
IREC Certified Master Trainer
Solairgen School of Solar Technology