AC power testing adapter idea

[Frankentronics]

Greetings,

As a beginner I don't know how much I can contribute to this forum, but perhaps I came up with an idea that some people here can find useful.

Basically, after I put together my own "Variac" I figured out that I didn't really have a practical (and safe) way to plug power chords into the Variac's receptacle, as many of those chords were just stripped wires. So, I went through my salvage bins and put together an adapter, that consists of an emptied shell from a wall wart and a set of speaker connectors.

It is all self explanatory from the images.





I find this to be very useful and versatile, as I can unplug it from my Variac and plug it into any receptacle. Or even put it into my pocket and take it to a friend's house, if I want to do any work there.

Hope some of you find this idea useful.

Regards...

[ovnr]

Or you can buy one of these, which are safer and actually built for mains stuff. Just a shame they're so shockingly expensive.

[james_s]

Cord, a chord is a combination of musical notes.

Be careful using adapters like that, those terminals are not designed for line voltage and may not handle much current. That said, for years I've used cords with a plug on one end and alligator clips on the other for purposes like this, potentially dangerous but certainly handy.

Those Quicktest adapters are great but about twice they price they ought to be IMO. That said it's a niche device with a small market, and they seem to have never got much if any traction outside the UK. Wasn't until Youtube that I'd ever heard of one.

[Frankentronics]

Cord, a chord is a combination of musical notes.

Woops! Still learning English. Thanks!

Be careful using adapters like that, those terminals are not designed for line voltage and may not handle much current.

I was wondering about current, actually. If there was a fuse inside the adapter would that do the trick? Just intuitively the fuse feels like a cat whisker, much thinner than the connections on the speaker terminals. It "feels" to me that the fuse would blow before there was any arching or melting going on at the speaker terminals. But I'm not experienced. I might be wrong.

[james_s]

A fuse might help, best approach I think is to make sure a test rig like that is never left powered unattended and it should be clearly labeled that it is a test device for temporary use and dangerous voltages are present on the terminals. This will depend on your household of course, you don't want someone who doesn't know plugging it in thinking it's something else.

[jeroen79]

If you want to know if it is safe then you should look for a datasheet.
That would specify the maximum current and voltage.

Try looking around on mouser/reichlt/farnell/conrad/whatever for a similar connector.
They usually will have a datasheet with it.

[PTR_1275]

I have numerous test leads around the workshop for various ac testing.

The leads that have bare wires or alligator clips on them are hanging up away from all the other IEC type leads, then when not in use the exposed wires are taped to the mains plug in such a way that you can’t plug it in without realizing it’s a dead mans plug. As soon as I finish using them, no matter how busy or critics other jobs are, it gets taped and put away.

I also have one of the cliff testing boxes. If I didn’t watch big Clive, I’d never known about them. Yes they’re a bit pricey, but for a bit of a niche product that hasn’t saved me more time than it cost, it was worth it to me (and it’s safe)

With the adaptor box you made up, it will work, just be careful when using it. The voltage shouldn’t be a problem but the current couldake things get messy quickly. Those connectors heat up, then the plastic melts and the spring pushes the plate through the plastic. Putting a fuse in there is a good idea, but I’m also not sure what you work with or are planning to use it for.

I would also make sure it’s out of reach of anyone else when you’re not around so someone doesn’t pick it up and plug it in without knowing what it is (as others have mentioned, warnings or something similar on it)

[Frankentronics]

OK, you all make good points.

I think I'll put together an upgrade with a fuse. I'm guessing a 1A fuse should be OK, right?

What I plan to use this for, mostly, is to test salvaged transformers. I am planning to learn about building audio amps and power supplies for such amps.

This adapter would only be used to quickly weed through a bunch of salvaged transformers, so I can select the one I wish to use for the project. Once I know which transformer I want I would make a proper AC connection and work further from there.

Is there perhaps a better way to plug transformers to my Variac? When I built the Variac I started plugging the ends of stripped power cords into the Variac receptacle and that looked dangerous. I also user alligator clips, but that looked dangerous, too, because there's always a tip of the alligator clips that remains exposed beyond the sleeve and things tend to move on an active workbench. And of course, it takes too much time to build a proper connector for each transformer I want to test.

But perhaps there are other economical ways of doing that.

Thanks...

[JacquesBBB]

I  am sorry to tell you that, but do not like very much your  adaptor.

I am concerned by the fact that some wire could be loose and you would get shocked while plugging or unplugging.

I  suggest that you take a standard power cord,   with a normal plug that you plug in your variac.  On the other hand,  you put
a box with your adaptors  for attaching bare wires. And if possible, with a fuse.

For my own use,  I  have a power cord  where one side are attached Wago  3 wires connectors

where I can attached bare wires.

Wago  are rated  for 400V, (peak 4KV), 32A


I can plug this  cord in the variac, or in  a  plug with  2 or 10 A   and 30mA differential  breaker, which I also use as a switch.

[piguy101]

Nice adapter! I'm still looking for something with a male mains connector and female banana jacks (preferably the kind that accept shrouded banana jacks) to use on a variac. I may end up making my own if I can't find anything.

[stj]

Or you can buy one of these, which are safer and actually built for mains stuff. Just a shame they're so shockingly expensive.

look harder.
http://cpc.farnell.com/unbranded/tb1/test-block/dp/PL15699
 

[Bratster]

Or you can buy one of these, which are safer and actually built for mains stuff. Just a shame they're so shockingly expensive.

look harder.
http://cpc.farnell.com/unbranded/tb1/test-block/dp/PL15699
 

If only I could get one in the USA near that price....

Right now I use a "suicide cord" with Wago connectors on the end.

Sent from my Nexus 6 using Tapatalk

[Frankentronics]

I  am sorry to tell you that, but do not like very much your  adaptor...

...For my own use,  I  have a power cord  where one side are attached Wago  3 wires connectors where I can attached bare wires.

Oh, no need to be sorry. This is why there are forums and I do want any constructive feedback.

I didn't even know about the existence of these Wago connectors. I'll look into this and possibly use one to make a better jig. The only thing that doesn't look too good on this Wago connector is how closely spaced the holes are. It just feels to me that there could be a short connection, inside, if braided wires are used.

look harder.
http://cpc.farnell.com/unbranded/tb1/test-block/dp/PL15699
 

I do like this, though, for a good price. Thanks for posting this.

[SeanB]

One Wago connection per wire, those are meant to join 3 wires ( or 2) in a junction box, and are pretty good at it. For your test lead you just have one per lead, so one line, one neutral and one for ground.

[Frankentronics]

One Wago connection per wire, those are meant to join 3 wires ( or 2) in a junction box, and are pretty good at it. For your test lead you just have one per lead, so one line, one neutral and one for ground.

Oh I see. So that's not the best solution.

However, after some more Googling I did find another connector.



https://www.banggood.com/3-Pins-Quick-Fix-Push-in-Clip-Spring-Connector-Cable-Terminal-Block-for-3528-5050-LED-Strip-p-1162333.html?rmmds=cart_middle_products&cur_warehouse=CN

There are no listed ratings and it is designed for 12V LED strips. But I wonder if it would be better than my initial speaker connector idea, with a fuse, of course. Although it wasn't designed for mains I don't see how it would start melting if there was a fuse.

[stj]

well.
these say 10A but BG says dont go over 1500w which at 240v is 6A
https://www.banggood.com/20pcs-3p-CH3-Quick-Connector-cable-clamp-Terminal-Block-Spring-Connector-wire-without-welding-screws-p-1001559.html

these say 32A
https://www.banggood.com/Excellway-ET25-235-Pins-Spring-Terminal-Block-Electric-Cable-Wire-Connectors-5Pcs-p-1129219.html
https://www.banggood.com/5Pcs-235-Pins-Reusable-Spring-Lever-Terminal-Block-Electric-Cable-Wire-Connector-p-1103030.html

[JacquesBBB]

One Wago connection per wire, those are meant to join 3 wires ( or 2) in a junction box, and are pretty good at it. For your test lead you just have one per lead, so one line, one neutral and one for ground.

Oh I see. So that's not the best solution.

However, after some more Googling I did find another connector.



https://www.banggood.com/3-Pins-Quick-Fix-Push-in-Clip-Spring-Connector-Cable-Terminal-Block-for-3528-5050-LED-Strip-p-1162333.html?rmmds=cart_middle_products&cur_warehouse=CN

There are no listed ratings and it is designed for 12V LED strips. But I wonder if it would be better than my initial speaker connector idea, with a fuse, of course. Although it wasn't designed for mains I don't see how it would start melting if there was a fuse.

Yes, with the Wago, you need one per wire.

I know the above connectors. I bought some of them.  They are supposedly designed for 250 V , but of very low quality.   I would use  them only for low voltage,
and not for main.

I feel that the Wago solution is much safer.  I would fear to make the main wire loose, while attaching something.
Of course, one should only do that after  shutting down the main, but  if you have double security, it is better.