need to remove ballast and wire for LED lights.

[Shocked1]

I have a 4-bulb fluorescent light, previously wired for T-12?, now wired for T-8, with a bad ballasts. I think my tombstones are non-shunted. It looks like I can just remove the ballast, direct wire the whites to one side of each of one end's tombstone, and the blacks to the other side of the same tombstones, cut and cap the wires to the other end's tombstones and get single-ended bulbs. If I do this, and my tombstones are shunted, it looks like it will short out and maybe burn my shop down. Is there a way to test my wiring that minimizes the risks, or a way to wire it where it won't matter if the tombstones turn out to be shunted?

 

[Mikegh]

Ah shunted tombstones I remember that Americanism

Sorry I can't help with specifics but won't be that complicated wiring the tombstones ,just match the fluorescent wiring to the led spec

But how much are you saving $$ with this conversion over new fitting , sometimes you're losing efficiency on these conversions between old dirty covers and cheap led lamps

Short answer anyway ,you're probably better off just buying a new fitting

 

[Mikegh]

So let me dig up some info here:


"To retrofit a single-ended power (SEP) LED tube, the electronic ballast needs to be removed. An electrician can quickly cut the L/N wires from the ballast, cut the socket lead wires and connect the input wires to one end of the fixture in order to bypass the ballast. The LED tube will connect directly to the voltage line flowing into the sockets. The second tombstone acts as a stabilizer to hold the tube firmly in place. No electricity flows through that side. For safety reasons, a qualified electrician should perform any retrofitting."

What Type of Socket Do I Need (Shunted vs. Non-Shunted)?

Non-shunted and shunted tombstones (named after their shape) are the sockets or lampholders required for any retrofit tube install. This blog covers the differences between the two types and how to detect them. We will also cover why Sunco Single-Ended Power (SEP) Type B T8s require the removal...

www.sunco.com

So the above is a SEP led tube with the supply connected direct to one tombstone (end cap), other side merely retains the tube

Requires a non shunted tombstone so you'd be verifying you've no continuity across the cap before connecting supply to one end only

 

[Mikegh]

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So that type there is compatible with either tombstone

Shunted tombstone can only be used for DEP

Also is plug and play and can be fitted direct without removing compatible ballasts at all, so quite versatile

Can't say I've ever fitted any of these things , seems pointless upgrading old fittings ,.just swop them out for fittings with brand new covers

 

[Mikegh]

I have a 4-bulb fluorescent light, previously wired for T-12?, now wired for T-8, with a bad ballasts. I think my tombstones are non-shunted. It looks like I can just remove the ballast, direct wire the whites to one side of each of one end's tombstone, and the blacks to the other side of the same tombstones, cut and cap the wires to the other end's tombstones and get single-ended bulbs. If I do this, and my tombstones are shunted, it looks like it will short out and maybe burn my shop down. Is there a way to test my wiring that minimizes the risks, or a way to wire it where it won't matter if the tombstones turn out to be shunted?

So finally getting round to your question

For the SEP type there you need to check for an open-circuit across the tombstone you're connecting the supply to

The original T12 tombstones would be non- shunted, reasonably certainly

 

[Shocked1]

So finally getting round to your question

For the SEP type there you need to check for an open-circuit across the tombstone you're connecting the supply to

The original T12 tombstones would be non- shunted, reasonably certainly

Thanks for the input, Mike. My fixtures are in good shape, and cutting wires and reattaching cost me nothing [well, except for bulbs]. Eight new fixtures cost about $3-400:00, and lots of work on a ladder, so I'd prefer to go the zero-cost way. I have an old continuity tester, that I think indicates non-shunted / no continuity. I think I might buy a new one I can trust and re-check. I just didn't know if hooking it up this way and getting it wrong would flip a breaker and not be a big deal, or do real damage to my shop.

 

[Mikegh]

Your black and white goes direct to the caps on one side only for the SEP

All other wiring and caps is redundant

There's a model above that does both type caps anyway