What’s involved in a site survey? And why it’s critical to good energy management
By Anthony Schoofs, CTO, Wattics
January 13, 2017
Electrical installations in commercial and industrial sites are typically the result of a long history of expansions linked to changing needs and requirements, for the majority not documented. Electrical installations all come with their own little surprises, that you generally discover once project proposals and payment terms are agreed and signed off, i.e. too late. Any monitoring and targeting project must therefore start with a proper site survey to specify the scope of works for the project proposal; any other approach could end up very costly.
Site surveys are carried out to define the exact requirements to support an energy efficiency project’s execution and validation. In particular, site surveys are necessary to:
- Gather information about the electrical installation (and all potential surprises)
- Devise clear energy monitoring strategy
- Quote what is going to be installed
- Serve as reference to go back to when managing conflicts with the end-customer
Step 1: Find out what the customer wants
Although project specifications are mostly driven by what the project is trying to achieve, precious insights can be gathered by discussing with the end-customer. Very often these discussions will add additional monitoring requirements and drive the project towards a successful outcome. A number of questions should be asked to the end-customer:
- Have you got any metering system in place already
- Do you have archived data sets you want to integrate
- Do you want specific equipment to be monitored
- Do you know how energy is used throughout the site
- Do you know the main energy offending machines and areas
- Are you interested in electricity, water and gas metering, or other
- Have you already conducted an energy audit to base our work on
This information will help focus the site survey and match the customer’s expectations in the project proposal. It will allow you to quote for the exact tasks that will be conducted, and avoid you going the route of trying to get extra payments from your customer. This usually ends up going the extra mile for free to close the project and get the full payment.
Step 2: Picture the electrical installation
Electrical installations are generally the result of original installations combined with a number of changes and upgrades made over the years to accommodate site expansion or new business requirements. Subsequently, electrical wiring is very often not optimised or logical, and more importantly poorly documented. Now that you have got some sort of introduction from your customer through well-targeted questions, a number of more technical checks should be made to provide you with the most up-to-date information.
- Get your hands on the electrical wiring diagram and ask the site electrician to explain it to you and to point all recent changes that have been made
- Take a tour to the main switchroom where the building gets its power from the grid, and where all the smaller distribution boards are fed from. Try to match circuits to sub-boards with the wiring diagram, and write down any discrepancy. This task will provide you with a high-level picture of how power is distributed within the building. The idea is that you don’t miss that extension circuit that is not on the diagram but that is very important and that nobody told you, that could end up costly.
- Walk-through the building to locate the distribution boards powering areas of interest for your customer, and note their type as a way to assess the monitoring complexity
- Pictures, pictures, pictures… note any information you can find such as circuit labels, wiring sheets, cable size, MCB size, etc, anything that will help you later on to remember the setup, specify the right equipment, and estimate the installation time. For example, bus bars, double/multiple-fed circuits and generally any circuit rated over 600A will require more expensive CTs and Rogowski coils.
Finally, labeling is one of the most important factor to a successful installation, and non-existent or incomplete labeling of circuits can jeopardise your profits. No labeling means that the link between electrical loads and circuits monitored is unknown. When labels do not exist or exist but are incorrect or meaningless then the measurements provided on your energy management platform are misleading. Inconsistent labeling should be identified during the project proposal stage, because customers will otherwise expect you to label circuits (which is lengthy and difficult) at no extra charge, leading installation to be lengthened, postponed or canceled.
Step 3: Find out how you will deploy your energy monitoring system
Deploying a monitoring system comes with a number of requirements in terms of power supply, access to cables and access to the Internet. You must clarify during the site survey how this will happen:
- Where can the meter be located (DIN rail/panel mount), will you need a separate enclosure
- Where will the CT leads pass through to reach the cable chambers of the meter(s)
- Is there a spare MCB and neutral that can be reused for the installation or must they be deployed. Can they be deployed on installation date considering board shutdown is necessary for that?
- Are wall sockets available to power up laptop during installation
- Can the customer network infrastructure be used to connect the monitoring system to the Internet
- Is there a wired Internet point in the vicinity of the board that can be used, will the IT department provide that in case
- Is the GSM signal strong enough should a GPRS/3G router be needed (you can check with your phone or use a signal analyzer)
Step 4: Discover annoying issues early
Some issues are more annoying than others, as they can dramatically delay an installation and occur massive hardware and labour costs that would not be budgeted in the first place. Some examples of recurrent issues are:
- Components of a same machine are fed from multiple distribution boards in different locations, e.g. production line, meaning that metering equipment must be deployed at multiple locations.
- A circuit feeds more than one machine, meaning that metering equipment must be moved to the level down closer to the machine of interest
- Circuits can only be powered down during scheduled shutdown periods, meaning that circuit breakers and current sensors must be deployed prior to installation or at a agreed dates such as week-end
- Labels are non-existent or not clear, meaning you must go through a tedious labeling exercise
- Existing equipment does not work as expected, e.g. existing pulse meters are defective and do not issue pulses, meaning that you must take into consideration troubleshoot of 3rd party systems
Step 5: Size effort for dealing with 3rd parties
Now that the electrical wiring is pretty clear and you have a picture of how you’re gonna tackle the metering aspect of your installation, you must not forget the work related to dealing with all the various organisations over the course of the project. Very often project management proves to be time-consuming as you must go to site and meet various people to get the information you need. The items below should be considered and discussed with your customers:
- Switching off loads: is management pre-approval required, should a person with authority be present during installation, can machines or circuits be switched off, etc
- Integrating 3rd party systems: who can get you authorization to request data from the energy provider or connect loggers to Utility meters. Communication with city councils and energy providers can be tedious and lengthy, datasheet and technical information may not be available.
- Obtaining tariff information: what are the tariff and charges applied, is the tariff structure standard
- Access to IT network: what are the requirements, is the IT team aware and available to help.
- Access to on-site electrician: can site electrician label circuits and install circuit breakers before installation date. Is on site induction required?
That’s pretty much all you should need, put all your notes together and get started with your project proposal!