Grommet size applications

[Blooze]

Ok, stupid question, but how many of the 16awg transformer wires can you safely put through one of the 1/2” rubber grommets Doug sells?

My transformers have 6-7 wires and it seems mighty tight.

[sluckey]

All of them.

[Blooze]

I can jam em in there. I have a Hammond 370BX for a preamp that has 10 wires on one side and I think 8 on the other.

[sluckey]

I very seriously doubt there are any 16AWG wires coming out of that Hammond 370BX. But, 10 wires is a lot to poke through a 1/2" grommet. Don't fret. Just go to Lowes and get a 5/8" or 3/4" grommet. Cheap. Pick up a reamer or unibit too if you cant drill a larger hole.

[Blooze]

Thanks Sluckey. Right now I’m just using the MPS transformers for my GA-18 build and with all the extra wires for the OPT I was worried about it being too tight in the 1/2” grommet. I suppose some baby powder or something might help to get them all in. Like I said, it was pretty tight. Tight enough to yank the grommet out of the chassis.

[Blooze]

I checked my 1/2" grommets and the panel size is correct at 1/2", but the ID is just a little over 1/4", not 3/8". If it was 3/8" the wires would fit much better. I live in a pretty rural area and our local stores don't have much if any selection for grommets unfortunately. I'll need to get online and order some.

[sluckey]

You could just enlarge the chassis hole a bit so the grommet fits loosely. Then when you jam all the wires through the grommet it will stretch a bit to accommodate the wires and probably swell to fit the chassis hole just right.

[EL34]

Many amps have two grommets
One for each side of the PT

[PRR]

> I live in a pretty rural area

No Tractor Supply?

(Altho here, we have more-better Tractor Supply stores near The City than out here in the sticks....)

As EL34 says, you can have multiple holes and grommets even for a single transformer or winding. There is a slight preference for both legs of one winding in one hole, so the magnetic field cancels, but this is more about 100AMP electric power in conduit than 0.1Amp tube stuff through a sheet.

[Blooze]

Many amps have two grommets
One for each side of the PT

Never seen two on each side of a transformer. It is all I can do to squeeze all the output wires from one side of my OPT through one of these 1/2" grommets I picked up from Doug. The PT is almost as bad. Needs a grease zirk. If they actually measured 3/8" ID it'd fit without having to force it. I have the 1/2" from a couple different places and none of them are the 3/8" ID they say they are supposed to be.  First world problems.

> I live in a pretty rural area

No Tractor Supply?

(Altho here, we have more-better Tractor Supply stores near The City than out here in the sticks....)

As EL34 says, you can have multiple holes and grommets even for a single transformer or winding. There is a slight preference for both legs of one winding in one hole, so the magnetic field cancels, but this is more about 100AMP electric power in conduit than 0.1Amp tube stuff through a sheet.

By the time I pay for gas to get to the nearest store, I could just pay shipping and order some.  I need to place an order for a few pedal parts from Mouser anyway. Really was just curious how tight you could jam them in there without causing issues.

[PRR]

Many amps have two grommets - One for each side of the PT

Never seen two on each side of a transformer.....

I think he said one each side. Not two each side.

Not that that would be wrong.....

[Blooze]

Many amps have two grommets - One for each side of the PT

Never seen two on each side of a transformer.....

I checked my transformer specs and the PT and OPT use 20AWG. One side of the OPT has five leads and that grommet just feels like I'm jamming them in there. One side of the PT has 7 leads and I haven't tried it yet.

I know, of all the things I could be fussing about.