Power cord strain relief bushing too small

[bnwitt]

So for quite some time I've been using 16 gauge 12' long power cords on my amp builds and it is a real bear to get them installed in the typical D hole strain relief busing.  It seems everyone sells the same strain relief bushing which works well with 18 gauge power cords but not the larger 16 gauge cords. I am wondering if there is one available with a larger interior diameter for this purpose.  Anyone know?  As it is now I have to use a pair of pliers on the bushing and strike them with a hammer while pushing down to get the bushing to seat in the chassis hole.

[mresistor]

Barry - what I've done in that situation - (1) applied heat prior to squeezing with strain relief grommet pliars ( I made pliars from long handled adjustable pliars from harbor freight, ground the teeth off for a smooth surface)
(2) you can take a smaller rat tail file to the inside of the strain relief grommet to "open it up" a little.


But my final solution was to find a source of 10ft 18ga computer power cord and then snip the end off..  I found some cheap at wallly world dot com with US color coded wire. 

[92Volts]

Hoffman, Mojotone and Partexpress (pretty common sources for amp parts, including the strain reliefs) both sell 18 gauge power cords. I'm sure Mouser sells them too, except searching their site is a nightmare.
Hardware store power cords tend to be larger... but getting a smaller cord may be as easy or easier than getting a larger strain relief.

I've used nail clippers to enlarge the inside of some of these strain reliefs, but only the ones meant for flat zipcord, not pre-shaped to a round power cord... basically, I bought the wrong ones and needed to enlarge them just to fit OPT wire, let alone a power cord. A file as mresistor suggests might be the best solution if you're already close to the final shape/size of the wire.

I've also run a power cord through a rubber grommet and achieved "strain relief" with a knot and/or loop around some component before making electrical connection inside the amp... I felt the result was reasonably durable and safe but I wouldn't 100% recommend this as a long-term or "best" solution.

[sluckey]

I quit using those D-hole strain reliefs when I discovered these. Much better and more secure. Several sizes and quantity packs available. 1/4, 3/8, and 1/2 NPT will likely cover any cord you would put on an amp.

Take a look...

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.TRS5&_nkw=Cord+Grip+Cable+Gland+&_sacat=0

[DummyLoad]

https://www.wireandcableyourway.com/18-3-soow-portable-cord-600v-ul-csa.html


--pete

[bnwitt]

Thanks everyone.  I do prefer the 16GA over the 18GA cord and that is why I have this dilemma.  The chassis I buy all have the D-hole in them and they are all the way to the left where I couldn't really cover them up with the rear plate.  I'm familiar with the gland cord holders from my solar work but I've not seen them in a D-hole shape.  I'd use them if I could get one that fits the typical chassis D-Hole

[mresistor]

Are you using the correct size bushing ?       https://www.heyco.com/Strain_Relief_Bushings/product.cfm?product=Original-Strain-Relief-Round-2&section=Strain_Relief_Bushings

[sluckey]

I'm familiar with the gland cord holders from my solar work but I've not seen them in a D-hole shape.  I'd use them if I could get one that fits the typical chassis D-Hole

Don't hold your breath. Just continue to roll up your sleeve and crimp the hell out of that strain relief until your oversize power cord fits. 

Or you could use a step bit to ream that D-hole round and to the proper size. Probably take less than a minute once the step bit is chucked.

[bnwitt]

Are you using the correct size bushing ?       https://www.heyco.com/Strain_Relief_Bushings/product.cfm?product=Original-Strain-Relief-Round-2&section=Strain_Relief_Bushings

Mresistor
Well all the usual vendors sell the same one.  I'll check you'r link and see if I can get the correct one for the standard panel hole and cord size.  Thank you sir.

[DummyLoad]

18AWG is rated to 10amps. 16awg is bigtime overkill. crimping down 16awg with a  18awg strain relief is worst thing you can do to that power cord.


--pete

[bnwitt]

18AWG is rated to 10amps. 16awg is bigtime overkill. crimping down 16awg with a  18awg strain relief is worst thing you can do to that power cord.
--pete

I don't use 16 gauge for the power rating but for the toughness.  I find the 18 GA cords too flimsy to put on an amp I hope to last 25 + years of gigging.  I have lately been grinding the bushing for the 16 GA cord but that is hit and miss.  I would prefer the correct size bushing.

[PRR]

I used 16ga to wire some 0.1 Amp sense-wires from my fusebox to a meter. As you say, tough is good, especially when tapping raw 240V above a cellar floor.

But in that case I used electrical junction box fittings. These may not be right for a stage-amp's constant flexing. My case was more a fixed-install which doesn't move.

I always hated the Heyco. The "gland" fittings are better. I think that is what I used on a student/studio amp some years back.