The separated grounding system myth

As one of my teachers on “grounding systems” say’s: “The only way that you can separate to grounding systems is, if you place one of them on earth and the other one on the moon”. I agree, but this is one of the most frequent questions we get asked when we are inquired about grounding systems. The main thing is this: “you need to have ALL of your grounding systems connected together”, this is true because if you do not have them connected together, you can have grounding loops and in an event of a lightning storm your systems will not be at the same potential, causing that energy from a lightning strike enters trough your earth or neutral, causing damage’s to your electrical equipment and possible harmful injuries to the personal working at these sites.

You are going to hear all kinds of excuses for not connecting the systems together, mainly from the telecom and IT departments. This is cause mainly by misinformation and ignorance about grounding from the part of these engineers. You have to try and convince them that the only way that their systems would be secure is if they bond the grounding systems together.

What you need to explain to them?

This was the way that I was taught this years ago and it does not get any simpler terms than this. Tell them the following: Their “grounding system” is like a boat in open sea, if you have two separate systems, is like having two separate boats, etc. In the event of a “wave” (ex.: Transient, lightning strike, etc), it is preferable to have all your equipment in the same boat, this is because, this surges of energy can create a difference in potential, that can damage your other boat (or system), if they do not go up and down with at the same time with this wave. Do you get the picture?

Remember that grounding is the base of your Power Quality strategy. If your grounding is not good, all your other efforts would be in vain and your personal and equipment will not be safe.

If you have further questions on this or other PQ topics please send them to: jaming89@gmail.com.

Metering and Sub-Metering

If you want to know how much energy you are wasting, your first step is to measure your site. You have a couple of options that we recommend:

1.- You can purchase an Energy Audit. This is a fast solution if your site is experiencing power quality problems and also to make sure of what exactly is your energy consumption. Be sure to contract with an experience team of engineers. Also one that gives you a report with solutions for your issues. It is important to know that if your site is big enough, we recommend that you buy a Power Quality Logger of your own and train a dedicated personal of your engineering department to do the audits.

2.- You can install indirect power quality or energy meters. Depending on the facility that you are managing, you can buy one or several meters to do constant audits and assign goals or quotas per department. For example production and engineering can monitor for stops cause by power quality problems, correct them and make sure that they do not happen again. You can have a Power Monitoring Software that can log all the events and can set up alarms in your system, so it acts on them and send messages to the incumbent personal that can solve or mitigate the problem.

The two previous recommendations pertain the Metering part of the article. Now lets talk about Sub-Metering.

You can Sub-meter with one or several indirect digital meters. You can do this to bill your tenants electricity or to measure the energy consumptions per department or company division. Than you can bill them accordingly and in most cases you can also ensure that they apply energy saving or power quality solutions that will improve the companies bottom line. You can also use sub-metering solutions to bill your tenants for the energy that is supplied by your generator set and collect appropriately.

Questions? Contact us @ jaming89@gmail.com

 

The color of light

Reading about this subject this week, we notice again that in my country(Dominican Republic), we have a huge problem with light color. The IESNA Handbook, states that is very difficult to recommend the right color of light for and office application, since people tend to like warmer or cooler lights, depending on their location. We mainly advise our customers to purchase 4100K or “Coolwhite” or in other cases 3500K a warmer light color. From our readings on many articles and from our experience we have seen that 4100K is a more productive and pleasant color all around. The problem is that in my country, people love 6500K or “Daylight”, they pensive it as brighter and is not, we show them manufacturer comparisons and in most cases they are the same as 4100K (in some cases 4100K has more lumens). I recently tried to convince a School to take the technical approach to their color of light decision, but they had already made studies and surveys with students and their personal, and decided that they liked better 5000K color. I told them that this color was rarely used in their circumstances and that the spec and appropriate color for their application was 4100K. We discuss it and the opted to consider it as an option.

People in charge in my country tend to make the decision in terms of their likes or dislikes and not by the technical or approve norm for the application at hand. This puts the engineers in a corner and they tend to do what they are told to avoid the conflict with the owner of the job. This is the right choice if you still want to do business with this customer, but it violates your code as an engineer. The thing is that if every engineer acted according to this code, the owner would have to settle for the write spec and not his own EGO spec. The truth is that if you do not do it, somebody or some “engineer” appears that does what his told to regardless all codes and specs and wins the customer.

We still hope that in our lifetime this changes in our country and we are doing our part in trying to change. In the mean time, try to explain yourself as best as you can on the pro’s and con’s of certain decisions you have to recommend or that your current boss wants you to do. At the end is going to be his call, but you will feel better in the morning.

We will keep you posted on how our bid ends. Thanks for reading.