In data center installations, grounding of all equipment is essential for three reasons:
- Prevent shocks to personnel by touching ungrounded equipment when their body provides the ground.
- As a defense against natural lightning strikes or sudden overloads of the electrical power grid caused by a variety of reasons.
- To prevent data loss.
A shock from touching ungrounded electrical equipment that is typically used in a data center might be uncomfortable, however it would be rare if this type of shock was life threatening.
In areas subject to lightning strikes, if the building is hit, problems may arise. The metal on the outside of the building or the metal within the interior, such as piping or conduit in the walls conducts electricity. What happens is that the bolt of electricity travels down the path of least resistance, potentially destroying all equipment it passes through until it finds the ground.
This is why lightning rods are used on the roofs of any building in areas subject to frequent storm activity. A lightning rod is a very simple thing. It is a metal pole put up as high as possible in the air above all the roof surfaces of buildings. This lightning pole is then connected directly to another metal pole buried deep in the ground a safe distance away in a secure area. If lightning happens to strike in the area, it is attracted to the pole and the electrical discharge goes to the ground (the Earth itself) without harming anyone, or passing through and potentially destroying any equipment on the way.
When equipment is not grounded properly, a sudden spike of electrical energy from lightning or other sources may pass through the equipment connected to the circuitry. Because of this, ungrounded circuits may cause data loss. It is better to prevent this by grounding all equipment properly, than to deal with the consequences of data loss thereafter. This means using good cable management to connect power to data center racks
How Common is Lightning?
Lightning strikes are more common than one might imagine, especially in certain areas. According to National Geographic, lightning strikes somewhere on the Earth, on the average of 100 times per second or over 8 million times each day. A single lightning bolt contains up to one billion volts of electricity. Even though the common idea is that lightning does not strike twice in the same location, this is not true. Lightning can strike again in a near spot if the conditions exist to attract it to the spot.
There are plenty of examples of lightning hitting the same person more than once. Most commonly, these are rancher types in parts of America subject to thunderstorms who have to be outside quite a bit due to their occupation.
Data Center Grounding
It is not only lightning strikes that cause potential problems. Sometimes there is a temporary overload of the power grid that sends an unwanted electrical spike down the power lines to unsuspecting data centers.
Everyone is familiar with power strips for computer and electronic equipment. These are designed to block any damage to isolated equipment from sudden power surges. Data centers need to think about this on a much grander scale. There are a couple of reasons for this.
First, the data center is drawing lots of power so the potential of a problem from an ungrounded circuit is amplified. Secondly, it is more cost efficient to protect the entire data center than to try to protect the individual or isolated equipment. Power strips with surge protection are fine for a handful of computers. When the number of computer servers increases to thousands, power strips are no longer a cost effective solution.
Ground everything in a data center without fail to make sure there is adequate protection from power surges, lightning strikes, and other electrical inconsistencies that may occur. Do this to avoid data loss and down times from power surge problems.
Katrina is a product specialist with the leading server rack engineering and accessories company click to find out more.