Advice on Non-Shunted T5 Sockets

jimmy40741

Member
I thought one of the ballast was going out on my TEK light a couple of months back so I quickly ordered a new ballast (it's an AccuStart Triad). The ballast wasn't going bad so since I have a brand new ballast laying around collecting dust I thought I would add some supplimental light to my 125. All I need is some end caps or sockets to do this but I am a little confused about them. On sunlight's (and other) sites they state "Program start ballasts require non-shunted sockets." I had been looking at the waterproof T5 end caps from Icecap, but it doesn't say whether they are shunted or non shunted. Does anyone know which they are? Or can anyone tell me if a socket is only shunted if it is listed as so and all others are non shunted?
A little more info, I have found quite a few gardening and reef sites that sell non shunted T5 sockets exactly like what is in the TEK light for $1.12-$1.50 each. But every one that I have found wants to charge $10.60-$18.00 in shipping. So I figure that if I am going to have to spend that much on shipping I might was well get the good end caps, that's why I am asking about them.
 

scsinet

Active Member
Shunted ballasts merely connect the two pins of the lamp together internally, non-shunted ballast bring each pin out to a separate connection back to the ballast.
Many manufacturers make both flavors of the same socket, so a shunted and non-shunted socket may look the same visually.
There are two relatively simple ways to tell. The first way is to look at the wiring to the sockets, non-shunted sockets will have two wires going into them. The catch though is depending on how the fixture is wired, shunted sockets may also.
A more sure way of knowing is to compare the wiring diagram of the ballasts. Usually the wiring diagram for a particular ballast is located on a label on the ballast's body. If the wiring diagram shows two separate wires from the ballast to the lamp, then it's a program start / rapid start ballast like the new one you got. If it shows just one, with the pins of the lamp connected electrically, then it's an instant start ballast requiring shunted sockets.
Here's the real issue you may run into... if the light fixture uses a remote ballast, and the existing ballast is instant start, there probably aren't enough wires going through the cabling from the ballast to the light to support your new ballast, in which case I'd return the ballast and get a different one that fits the bill.
The first pic below depicts an instant start configuration, the second a rapid start. See how the instant only has one wire going to the lamp? Those sockets would be shunt sockets, where the pins are tied together internally.

 

jimmy40741

Member
Thanks for the quick reply.
TEK lights use a program start ballast, so that's what I ordered and have sitting around. So I know that I need a non shunted socket to go with this particular ballast.
I have done some looking around on the net and I can't find any pics of the icecap end caps with attached wires, so I am thinking that they don't come pre-wired. But I have found pics of their pre-wired retro kits that look like they use the same endcaps, and they are two wire. So if anyone who has bought these particular end caps can confirm to me that they are infact 2 wire I would appreciate it.
I'm not going to run into any issues with the fixture because I am not working on one. As I stated before I have a ballast sitting around collecting dust and figure I will use it to add some more light to my 125, so I am going to do a DIY add on. I have the ballast, plenty of wire in my garage from 10 to 22 gauge, a plug and cord, and a canopy to mount the lights in, so all I need to get to finish it is the endcaps.
Also, isn't the two bulb configuration in the second image incorrect? Shouldn't the yellow wires also be going to the second bulb, or at least pigtailed off of the first bulbs wires?
 

scsinet

Active Member
That's just a common wiring diagram that I found. It's not necessarily representative of any particular ballast, but yes, in most cases, the yellow would be paralleled to the second lamp.
 
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