The relamping approach
More recently, retrofits have been migrating toward systems where LEDs can fit directly into double-recessed T12 sockets. These systems typically come in two varieties.
The first is a self-ballasted LED tube. The power supply is contained inside the LED tube, so the existing ballast is bypassed. The socket is still used to supply primary power.
The second variety is a preassembled ‘stick’ with (a) LEDs that fit directly into the socket and/or (b) an extrusion carrying the LEDs with an end cap that mates to the socket.
As both of these varieties offer the benefit of using the socket as a holder for the LED system, they enable the undertaking of a T12-to-LED retrofit installation that is very similar to a simple relamping.
The first option offers the benefit of no extra wiring. Self-ballasted LED tubes typically integrate low-cost power drivers, however, which can be problematic given the lack of a heat sink (i.e. a passive heat exchanger, which transfers and dissipates the heat away from the device) and the types of components used. The second option does require additional wiring, but uses an external, commercial-grade power supply, which increases the system’s reliability.
It is worth keeping in mind any power supply, due to its complexity and number of components, is much more likely than an LED to fail. So, maintenance is easier if they are kept separate.
Given these factors, the preassembled LED sticks are becoming the preferred option for retrofitting cabinet signs previously illuminated by T12 fluorescent lamps.
“Many signmakers want a simple solution, where retrofitting is just like relamping,” says Daryl Foreman, vice-president (VP) of sales for Principal LED. “LED sticks are available in any standard lamp length, with both single- and double-sided versions.”
Moreover, these systems can be customized to meet any specific requirements in terms of depth, length, colour temperature and beam pattern, overcoming earlier limitations.