Safe electrics?

[wcndave]

I have this power supply from old computer.I want to put the c23 connector in the back so I can plug the cabinet in like one does a computer.

Its got all kinds soldered to it, fuse, 115 to 230 selector, some capacitors and so on.

Think its safe to take all that off and then cut the end off my extension and solder it to this?  Would use some heat shrink shielding of course...

[lilshawn]

if you must.

it would be easier to obtain another IEC socket (which is what the socket is called) and make a passthrough. (socket on one side and a plug on the other)

that way if your supply craps out, it's just a matter of unplugging the cord and plugging in another.

otherwise you're looking at chopping off the wires and extending them...then your power supply craps out...and you have to chop it out... on and on and on.

also: all the resistors and capacitors are on there to help provide some surge protection. usually they work those into the board but sometimes when short on space they just solder them directly to the socket comming in to the appliance.

[ed12]

hi
leave the socket in place
a power cord is dirt cheap
less then a beer

ed

[Drnick]

Do you mean install this into the back of your Cabinet and then run a smart strip or similar from it.  I take it that the Power supply in question is an old scrap unit and you are just cannibalising it for the IEC connection.

If so then yeah, lob all of that stuff off of it and solder your smartstrip/extension to it. Just make sure to get the cables all the right way round

I did something very similar but I just bought a fused IEC connector and then wired my extension lead to that.

[PL1]

One other consideration.

Are you going to have separate IEC connectors/power inputs on the back for your monitor, marquee, etc.?    

Seems like an IEC connector on the back of the cab (switched or unswitched) connected to a power strip or smart strip -- with the male plug cut off the cord -- would be much easier than hacking the current connector.


Scott

EDIT:  Thought you wanted to use the power supply instead of just the connector.  Stripping off the excess parts to act as a feedthru would be the same as the unswitched version above.

[lilshawn]

Do you mean install this into the back of your Cabinet and then run a smart strip or similar from it.  I take it that the Power supply in question is an old scrap unit and you are just cannibalising it for the IEC connection.

If so then yeah, lob all of that stuff off of it and solder your smartstrip/extension to it. Just make sure to get the cables all the right way round

I did something very similar but I just bought a fused IEC connector and then wired my extension lead to that.

i really have to stop posting here when I have to go to the bathroom.

now that i've re-read it, yes, chop away. you don't need all the extras on there.

first time i read it, sounded li..... never mind.

note to self... go pee THEN reply to posts.

[wcndave]

Sorry if it's ambiguous, dangers of using mobile to write posts, when you need to pee

I simply wanted to cannabalise the plug part.  I will cut it out, fix to back of cab, then attach power strip to it (i think the idea of attaching a plug to it (inside cab) is better, thanks), and will then have a cab i can plug/unplug at will rather than running a power cord through a hole in the back...  I just wanted to check that electrically it was safe, given the part had all these wotnots on it.  I know some electronics, but not a huge amount of electrics.

Thanks guys!

[PL1]

As long as the insulation between the conductors isn't damaged during desoldering and cannibalization, you make good mechanical/electrical connections, and you use some heat shrink or electrical tape to avoid shorts, you should be fine.


Scott

[lilshawn]

be sure to retain the hot/neutral configuration...mixing the wires can cause a potentially lethal situation should something go wrong.

hot=black
neutral=white
green=ground

always switch and fuse hot...not neutral.

sometimes cordsets come from china with "euro colors" in that case:

hot=brown
neutral=blue
ground=green/yellow

[wcndave]

There won't be a switch or fuse on here, its a straight passthrough was my idea.

The lead that plugs into wall will be fused, and the power strip in the cab will be fused + all the plugs in the cab are fused....

I am using all UK electrics.  Here in italy, plugs are not fused and neutral / live are interchangeable... so sticking with what i know (a bit better)

[lilshawn]

There won't be a switch or fuse on here, its a straight passthrough was my idea.

The lead that plugs into wall will be fused, and the power strip in the cab will be fused + all the plugs in the cab are fused....

I am using all UK electrics.  Here in italy, plugs are not fused and neutral / live are interchangeable... so sticking with what i know (a bit better)

LIVE AND NEUTRAL ARE NOT INTERCHANGEABLE!!!

PLEASE PLEASE PLEASE PLEASE I'm atheist and all, but, GOOD LORD don't!

from a safety standpoint you MUST NOT interchange live and neutral. most appliances with a metal box are grounded, those that do not (2 pronged plugs) have the neutral attached to the metal chassis. MIXING THE LIVE AND NEUTRAL PRESENTS AN ELECTROCUTION HAZARD IF YOU TOUCH THE EXPOSED METAL.

yes with AC there is no positive or negative. This is because the power neutral is basically a zero volt reference to the hot wire... you can safely touch a bare neutral wire.  due to the way AC operates it will seem normal and "Okay" but the modified appliance becomes very dangerous should the right circumstances arise.

if your plug coming into the cabinet is wired wrong...EVERYTHING inside the machine with a metal case/frame (monitor/power supply/computer/metal doors/etc) all become an electrocution hazard, because everything inside is now improperly wired.

if nothing else have an electrician do it.

[PL1]

Unless you live in an older place in Italy, you should have grounded outlets, assuming that Wikipedia is trustworthy on this one.   That means a 3-contact plug.

To keep from messing things up, you need to wire your whole cab for standard UK wiring including the IEC connector.

Get an IEC cord like this.


Verify which one of the outer contacts of the input cord wall plug connects to your cab's hot and MARK THE WALL PLUG BY THAT CONTACT.

Verify that ground is in the middle.

That leaves neutral on the other side.

Before plugging into an outlet you need to test it to see which side is hot and MARK THE OUTLET BY THAT CONTACT. (Multimeter to VAC, one lead in the center, the other to the outer conductor.)

Always match up the marks before you plug your cab in and you should be fine.   


Scott

[wcndave]

Thanks for the answers so far, although not sure I really understand them.

We have here 7 different types of plugs / sockets.

2 pin, 3 pin like the picture above, and 2 pin in a circle with two earths.



They then have combinations of wide spaced / narrow spaced, and thick / thin pins, giving a mind boggling combination.



In all cases the plug can be put in either way around, totally unlike UK plugs.

Whenever anyone plugs in a TV, washing machine, computer, fridge or whatever, no regard at all is given to which way around they are.

Plugging in the computer and screen in the cab is just the same as plugging in my home entertainment system i would have thought.  So not quite sure what all this advice really means.

Either every single electrical device here is a deathtrap, with no one ever getting hurt, or the electrical system is somewhat different.

I currently have a UK 4 way strip plugged into the cabinet, that is plugged in to an adaptor and then there are 2 Italian extension cords before the wall.  so the outside pins could be anyway around.

my intent was to solder the 4 way (or a plug as suggested above) onto the connectors of the salvaged IEC connector so I could plug / unplug my cab from the outside.

Given all the above, not quite sure whether that is safe, however can't see how it's any different in terms of what's connected to what than i have now.  or even the TV in my house....


I do appreciate all the help,

Cheers

Dave

[lilshawn]

okay, it seems everything there is "double insulated"


copy paste from wikipedia:

A Class II or double insulated electrical appliance is one which has been designed in such a way that it does not require a safety connection to electrical earth (ground).
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having two layers of insulating material surrounding live parts or by using reinforced insulation.
In Europe, a double insulated appliance must be labelled Class II, double insulated, or bear the double insulation symbol (a square inside another square).

because of the way electricity operates in north america what i mentioned is REQUIRED.

this is due to the fact that we run some appliances on 120 and others on 240 called SPLIT PHASE. we accomplish this by having 2 - 120 volt lines out of phase with each other (by 1/2 cycle). where the difference between the 2 lines at the peak of the voltage cycle is 240 volts. The problem is that one appliance plugged in to one outlet and another plugged into another outlet can be on either one of the 120 phases. appliances on different phases is not a problem except if there is a fault or improper wiring. then things get really dangerous really fast. this is why hot/neutral is so important here.
in Europe i imagine there are some places that do a similar 230/460 type of split phase power system but it would likely be in warehouses or other industrial application.

[wcndave]

Ok, thanks.

To be fair, most new appliances here have earth, it's the old houses and cables that often don't, but it is a requirement in all new builds now.

However earth was not the thing people were getting excited about, it was interchanging live / neutral, when all our many types of plugs are symmetrical exactly so this can be achieved.

Sounds like your different phases could be the issue.  I know when wiring up cabinets in my data centre that we should not power equipment in one cab from another cabs supply in case they are supplied with different phases and we get that double voltage issue you mentioned.

I think domestically here/uk it cannot happen.  For larger equipment typically > 5hp you'd use 3phase.  this would require a special circuit installed (expensive), or to use an inverter.  I know only one person who does this in house (well workshop).

So I think in summary I am safe to wire it up almost any old how, but i will keep them aligned to UK standards so at least from the outside of the cab to the equipment the same path is followed.

One final note is that each house here only gets 3kw (not enough for kettle and oven simultaneously), so apparently it's really hard to electrocute yourself properly without capacitors...

never heard of any toaster in the bath stuff here... 

[DaOld Man]

A lot of areas in the UK (United Kingdom, not University of Kentucky, sorry Wildcat fans!), use 220 volts on the appliances. If this is the case, then it is perfectly ok to swap the two mains leads. (But keep the ground straight).
Also, be sure your PC power supply is switched to 220 volts on the little red switch close to the power plug.
That is, of course, if your system is in fact 220 volts.
If you are not 100% sure, look at the labels on some of your kitchen appliances (small apps, IE toaster), see if they require 220 volts.

Also, 3KW is more than enough to sufficiently kill you. It only takes around 50 MA. (Just to give you an eye opener, 50 MA at 120 volts is around 6 watts, at 220 volts it is around 11 watts. 3KW is 3000 watts.)
So be careful, unplug your cab before doing any work inside.

One more edit, my first statement about the two 220 volt wires being interchangeable on UK systems may not be true. If one of the phases is grounded (as we do one of our 120 wires), then one of the 220 volt mains will be "neutral" to ground. If that is the case then the two phases are not interchangeable.
Its always best to call a qualified local electrician or the power company to find out for sure.

[MonMotha]

okay, it seems everything there is "double insulated"

They're either double insulated (a "Class II" appliance), or they have a conductive chassis which is grounded ("Earthed" in Europe - this would be a "Class I" appliance).

In fact, the only time live and neutral really matters is with old "Class 0" equipment where some exposed element of the circuit, such as the return shield on an audio connector, is directly attached to the AC line or where sufficient measures are not taken to prevent this from occurring in typical fault scenarios.  The classic example is an old radio where no transformer was used - things such as tube heaters were just strung together and placed directly on the AC line or a guitar amp that, either by design or due to trivial fault, references its circuitry directly to one of the utility lines.  Not exactly the safest design, and designs like this have generally been prohibited for sale for quite some time in most countries.  In this case, it is important that the neutral be the exposed reference since it's the only thing generally "touch safe".  Modern designs would use "safety ground" aka "protective earth" for this purpose and only use the AC neutral for returning actual power current.  Polarized outlets are somewhat of a legacy from an earlier era in electrical safety that stick around mostly for backward compatibility.  Lamp sockets in the USA still use the safety features, but do not strictly rely on them.

As a fun little tidbit, if you want to place a capacitor from neutral to ground (e.g. for EMI filtering), despite the fact that this should be a near-zero voltage difference, you actually have to buy special "Y rated" safety capacitors.  If you want to place a capacitor from an isolated low voltage system ("SELV" in standards parlance) like that commonly found on a laptop supply to pretty much anything coming out of the wall (there are various reasons for this), you again need to use Y-rated safety capacitors, but you have to either put two of them in series or get a special "Y2-rated" one that will preserve that isolation.

In general, if you have a system that preserves the difference between live and neutral, you should preserve it during any modifications you make.  Your building codes also probably require that be done in the building wiring if you have any means of polarizing plugs (i.e. plugs that can only be fitted one way).  Check your local building and electrical codes, of course.  If a system shipped with a non-polarizing plug, then it's probably OK to disregard live/neutral differences (assuming it was shipped with the right plug!).

[wcndave]

Thought wildcats was Arizona...

In the UK we use 220/230/240 v as it is variously labelled based on the method of measurement.  but all plugs only go in one way.  apart from shavers probably.  I am using all UK plugged equipment.

but I am now IN Italy, and here ALL plugs (domestic) are symmetrical, and therefore the lines must be interchangeable.

I didn't want to get into a huge debate, obviously there are significant differences that mean one should not mess around between countries thinking they know how it all works...

I don't turn off my cab, in the same way that i don't turn off my computer to plug in a USB device.  I guess that warning comes from the decased CRT screens that many "hard core" arcaders use.  I just have a computer with speakers and LCD screen, so working in cabinet is safe as working at my desk ;-)

[yotsuya]

Thought wildcats was Arizona...

They are. ---fudgesicle--- the Wildcats!