Category Archives: utility-scale-solar

When designing utility-scale solar energy projects, optimizing central inverters is a crucial aspect that project developers, EPCs, and stakeholders often overlook. The strategic placement and design of central inverters plays a significant role in...

This is a follow up to the article Design Recommendations for 1500V String inverters, where we only briefly mentioned "Free Voltage Drop" and wanted to dive in a little deeper here.

When we value engineer a large solar project, we can take advantage...

At Pure Power Engineering, our engineers work closely with project originators, developers and EPC firms to reduce the upfront capital costs of construction without sacrificing long-term operating costs. Given the dynamic nature of solar...

What is a "Neutral" conductor?

To an Engineer: A "neutral" is a current-carrying conductor that carries the unbalanced current in 3 phase systems, and is intentionally connected to the ground. In North America, the neutral is color-coded white or...

With 21 engineers between our NJ, CO, and CA offices, we have unmatched bandwidth to design your solar & energy storage projects fast. What does that mean for your project? Quick turnaround time from quality engineers means you can complete your...

Our first article 2014 NEC 690.12 Rapid Shutdown for String Inverters on Flat Roofs we explained the basics of implementing a rapid shutdown system using string inverters on a roof.  In that article, we gave a simple example of a single array.

The 2014 National Electric Code added a new section of code 690.12 requiring "Rapid Shutdown of PV Systems on Buildings".  Below is the first of 1 of 2 articles we put together to help you understand this code (here is the other: 2014 Rapid Shutdown...

Here is something that’s crazy, and yet we completely understand why they did it. Some evil genius put duct tape around the vents of a NEMA 3R transformer. If this transformer is heavily loaded it runs the risk of overheating, but at least snow cant...

Thermal (IR) cameras are a great tool for preventative maintenance and inspection of your PV system. With a little thermography “know-how” and some image focusing, problems can be discovered quickly before they create a fault or safety hazard in the...

On this system, the installer stacked ballast so high that it shades the modules at noon of each day. Why would anyone use a hollow block for ballast?

This photo is an excellent example of an inverter installation on the roof. Keeping the inverters next to the array allows the unfused string wires to be kept at a minimum length, increasing safety. Notice how the inverters are tilted to the north...

We were called out to investigate a performance issue at a site, and were shocked to see this wire management. We suspect the AHJ made this contractor install physical protection after the strings were installed, which is why the contractor cut the...

Just when I thought I have seen it all... Notice the mid-clamp that was never attached because the module was raised off the rail. Scary!

I appreciate Shoal's new arc fault technology as shown in this advertisement, however I was shocked to see the photo of a man standing on PV modules.

In a recent project we were able to value engineer a DC combiner feeder by running an overhead line rather than trenching an underground duct bank. The feeder would have been a 175 feet underground duct bank routed across a high traffic driveway...

In this installation, an AC panel board was located at ground level which combined the AC circuits from string inverters on the roof. We wanted to avoid entering the top of the enclosure with conduits, so a trough was used so that the feeders could...

During O&M we often find combiner boxes and disconnect switches with water inside them, despite the box being NEMA 4 and fully gasketed, no top or side penetrations, and weather tight connectors properly installed.

Here is a video I found on the internet, produced by American Apparel. I figured I would share it as an example how NOT to clean PV panels.

Many roofs are designed to support thousands of pounds of HVAC units and large air handlers, so the additional weight of an inverter is feasible in many cases.

Be careful with Aluminum Conductors

The cost savings of Aluminum conductors is too good to ignore. Both the engineer and the electrician must respect the differences between copper and the less forgiving aluminum. However, if designed and installed...