For those new to working with fluorescent lighting, or for homeowners or do-it-yourselfers, understanding the differences between components for various systems is essential.
Unlike traditional lighting options, with fluorescent lighting parts may fit a system but are not to designed to work with the system. Choosing between these components, such as non-shunted or shunted lampholders, will be critical to ensure the correct part is in place.
Simply looking at these lampholders, which may also be called tombstones because of their shape, is not necessarily going to provide you with the information needed to choose the correct part. In most cases, and if you are replacing existing components, the information on the component is the best resource. This is a simple way to make sure the correct part is selected.
Non-Shunted and Shunted
If you look closely at the bottom of the lampholder you will see there are two different sides to the tombstone, and at the foot of each of those sides there is a slot or plug-likes structure with two small holes.
The shunted lampholders have all only one side of the base that will be used, or in other words, there is an internal wire, a bridge, that automatically connects the two sides. The non-shunted tombstone will require two different sets of signals, or two wires on each side, since they are not bridged within the system.
In many models and options with the shunted lampholders, the one set of pins will be covered or blocked, helping to eliminate the risk of mistakenly using the incorrect tombstone in the fixture.
The Importance of the Right Tombstone
Failing to use the right lampholder, or using a shunted instead of a non-shunted, will result in one of two potential issues. The one factor to consider is the risk of electric shock, which can happen once the power is restored to the fixture if someone is still working on the unit.
The second possible result of the incorrect type of lampholder will be a failure of the fixture. By simply verifying the correct type of lampholder both of these issues can be avoided. Remember, the installation information or the product information available on the web should also indicate if it uses shunted or non-shunted lampholders.
If all else fails, and the information is not available online or through printed information, a quick call to the manufacturer will be able to clarify which option will be required as a replacement component.