How to select the perfect service entrance equipment for your needs
One of the many features of service entrance switchgear that may be customized is its exterior paint finish, which in a large facility can help differentiate it from distribution switchgear. Courtesy S&C Electric Canada
September 27, 2018 — With multiple options on the market, projects with huge budgets and tight deadlines looming, it’s easy to make the mistake of relying on the tried and true of the past. And why not? You have always specified the same service entrance switchgear for your projects before, so what’s the problem? Simply put: not all service entrance switchgear is created equal.
Choosing equipment that is inappropriate for your project is done at your potential peril. But it doesn’t have to be this way. Picking the correct equipment is easier than you think. So, what should you examine when selecting the perfect service entrance switchgear for your needs?
Service entrance switchgear vs. switchgear
Before we go any further, let’s take a minute to clearly define the difference between the terms ‘switchgear’ and ‘service entrance switchgear.’
In the simplest terms, switchgear is a combination of electrical disconnect switches, fuses or circuit breakers that are used to control, protect and isolate electrical equipment.
Service entrance switchgear, on the other hand, is the link between the utility grid and the end user’s system. It is also referred to as the point of common coupling (PCC), i.e. where two different systems operated by different entities connect. Everything that is upstream of the PCC belongs to and is maintained by the utility, while everything that is downstream of the PCC belongs to and is maintained by the end user.
One of the larger challenges with service entrance equipment, as with all other electrical equipment, is it must meet not only the Canadian Electrical (CE) Code and standards for switchgear, but also the utility’s operating requirements. Often, those requirements can conflict with each other, so the equipment manufacturer will have to find a way to reasonably accommodate both sides.
Not only is there a set of industry standards for manufacturers that governs the way switchgear must be built, but there are also other rules that must be followed for the utility to allow its workers to operate the service entrance switchgear.
For service entrance switchgear to be deemed safe by an inspector rom Ontario’s Electrical Safety Authority (ESA), for example, it must meet the criteria of Canadian Standards Association (CSA) C22.2 No.31, Switchgear assemblies. Even then, utilities have their own safety operating procedures that dictate switchgear design. This challenging relationship between manufacturers and utilities exists across borders in Canada and the U.S.
Typically, downstream of the PCC, the customer-owned switchgear must meet the CE Code and CSA standard. As such, it doesn’t matter where in the world it was designed or manufactured, so long as it is approved for use in Canada. And since it is installed downstream of the PCC, the manufacturer doesn’t need to know which utility’s network it’s connecting to, because it’s operated by the end user.
Service entrance switchgear, on the other hand, is unique in that it must be designed to work equally well with the utility and the end user—and, of course, each utility has unique requirements, based on its own safe operating procedures.
Overlooked and underappreciated
While it is clear the selection of service entrance switchgear is an important part of a project that needs to be addressed early on, it’s surprisingly often overlooked and underappreciated. That lack of foresight can place an entire project in jeopardy.
What frequently happens is standard equipment will arrive on-site, but because the specific power grid details were not worked out ahead of time, the utility could reject the service entrance switchgear for not meeting its requirements. For example, the switchgear could be built to CSA standards, but if the wireways are not sealed properly, as per the utility’s standards, then it may be rejected. The resulting delay in energizing the project could end up costing the end user significant amounts of money.
Being overlooked and underappreciated can also come from the mistaken belief that the rules and regulations in one place are the same across the board. For example, a consultant who has primarily worked in Saskatchewan, where the main utility for the province is SaskPower, may only be familiar with that specific utility’s requirements; whereas in Ontario, there are many smaller municipal utilities that each have their own requirements. So, a consultant who works principally in Regina and is knowledgeable on the corresponding standards, requirements and regulations cannot assume the same standards, requirements and regulations will apply for a project in Ottawa.
What to consider
The first thing to acknowledge is how critically important service entrance switchgear is as a link. If you have trouble with it, your whole building is out of power.
Secondly, as mentioned, it must be appreciated that not all service entrance switchgear is created equal. Some equipment is built to manufacturing standards that assume the best possible conditions, like a clean and dry indoor location, which is not realistic in many cases. You’ll have to deal with electrical rooms where there are sprinklers and where leaks and minor floods can occur. Equipment that’s tolerant for these conditions operates more reliably in the long run.
You’ll also want to consider quality. Well-built service entrance switchgear incorporates certain design features, such as welded construction for outer enclosure, power fuses (as opposed to current-limiting fuses) and copper bus instead of aluminum bus. Service entrance switchgear that is built to lower quality standards will result in more frequent maintenance needs, whereas equipment built to higher quality standards will reduce the number of outages.
Another factor to consider is customization, since every service entrance switchgear project comes with its own unique requirements. Retrofitting switchgear in an existing electrical room will experience certain design constraints, such as ceiling height. Standard designs typically occupy a larger space, particularly in terms of headroom, so a customized solution that is lower-profile may be required instead. Having to raise the ceiling in a room to accommodate your service entrance switchgear, after all, would result in immense costs or may otherwise be unfeasible.
The risks of the wrong selection
Imagine having equipment you purchased show up on-site that can’t be used. Well, if the service entrance switchgear as delivered does not meet the proper utility standards, then it will not be allowed to be hooked up. If you’re lucky, modifications to meet the utility’s requirements can be made on-site, but otherwise, the equipment will have to be returned to the factory to be completely rebuilt, thus further delaying the project, which costs everybody money. Contractors want to get off the job, get paid and move on. Owners want the building space occupied, particularly with residential properties that have closings. Delayed closings are very expensive and when funding is involved, banks get nervous.
Service entrance switchgear is a critically important link to the grid. If you don’t have a reliable link, the negative implications are huge: you’re out of power, you’re out of production and you’ll need backup generators.
Indeed, the importance of service entrance switchgear cannot be overstated. Making the right selection at the beginning means one less thing to worry about on your project later on.
Teddy Chettiar, applications director for power quality products for S&C Electric Canada, has more than 10 years’ experience in the power engineering industry.
This article originally appeared in the September 2018 issue of Electrical Business Magazine.
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