IEC mains sockets on US equipment

[Mick Bailey]

Bad idea for US touring artists in Europe; the ubiquitous 3-pin IEC connector for 220/230/240v fitted onto US 120v gear.

I've just inspected a Vox AC4 for someone over here from the US and the amp accidentally got plugged into 240v UK mains. Appears to have only blown the fuse, but who knows what the long-term is, especially the Chinese mains transformer. Even more confusing is the wording 630mA 250v right by the connector (referring to the fuse).

I suppose it's all down to cost.

[g1]

I'm not clear on which IEC connector you are referring to? Something other than the standard one used on North American gear?

[Enzo]

I could easily be wrong, but I think he is complaining that the internationally standard IEC power cord connector allows unsuspecting USA amp come over to 240v UK gigs, and the owner sees an IEC power cord and assumes it will work on his amp. And winds up with his 120v amp plugged into 240v simply because the cord fits.

[tedmich]

sadly I think fuses are the closest we can come to idiot proofing this issue!

[Mick Bailey]

That's right. Had three amps this year with the same issue and one of those needed the PT replacing as a result. Plus a US-only stomp-box power supply. It's an easy mistake to make where there's mixed equipment and loads of leads on stage.

Having an international socket is fine if everyone has roughly the same voltage. I would have thought a simple keyed plug/socket version could be used for 120v, similar to the 'hot' versions of the IEC connector used for kettles with the notch in the side, which prevents a standard lead being inserted (even though all other dimensions are the same).

It seems a bad idea to have a common socket in the equipment, given that the wall-socket end is country-specific.

[g1]

Seems like a bad idea to me too.
Just remembered that some of those IEC receptacles with integral fuse holders, flipping the fuse holder part upside down selects between 120 or 240V. They are not obvious and are hard to spot. The lettering is not even white or something that would stand out. Doesn't seem very logical.

[tedmich]

check out these high temp IEC sockets

IEC C16 Power Inlet, High Temperature | MPJA.COM
they only mate up with high temp cords so the odds are low someone would have one,
and maybe one of these right above it would help


but you'd still probably find some monkey cutting a notch in the male 240VAC cord connector...

[km6xz]

More than 1/2 the gear that comes into the shop is 120 or 100 volts so it is the automatic response to verify what voltage mains it was designed for. Almost never worried about that when working on gear in the US. only once in a while did a 230 v mains unit get shipped to us and no damage was done when turned on anyway. One this side of the pond, it is essential to verify, regardless of labels. For a tech, that is not a problem, just something you do but for a gigging musician who depends on support from club or concert staff to set up gear, it does cause real problems.

[R.G.]

Uneducated is fixable, but stupid is forever.

[teemuk]

Most amplifiers actually have a label in the rear that states what voltage the device is supposed to accept.


If someone is too stupid to ignore it then, IMO, he probably deserves to have his amp blown.

[g1]

If someone is too stupid to ignore it then, IMO, he probably deserves to have his amp blown.

Maybe if they know it and blatantly ignore it. But we're talking more about safety here, and those kind of issues are never handled in this manner. There is usually some kind of idiot proofing involved, we can't plug regular appliances into clothes dryer outlets.

[teemuk]

I don't get the analogy. Clothes dryer outlets are two-phase systems, amps and other generic electric appliances are single-phase.

IEC socket is universal around the world but usually amps only accept certain mains voltage. That should make alarm bells ring already. There's usually a label stating what mains voltage to input to the appliance. What else should be there? Doesn't the world have enough of different voltage systems and AC receptacle types already? And who says some idiot won't simply circumvent any of those with travel adapters you can buy from just about every store. If you import an appliance using different mains voltage to the country then why are you letting someone else to set it up improperly in the first place...?

If we want to idiot proof amps then we might as well start devising schemes against idiots who connect amps to speakers with instrument wire, who daisy chain speaker output jacks to input jacks, who fit solid metal blocks in place of fuses, or simply decide to open the amp up and stick their fingers to the terminals of a 500VDC filter capacitor.

Or how about spilling beer inside the amp, or dropping it to the bathtub while you sit in it playing your guitar....

I think there's a certain line where design efforts for making an amp reliable under normal use end and simply make way for all kinds aspirants for Darwin Awards or simple dumb assery.

[Mick Bailey]

I have some degree of sympathy, especially for a US artist coming over and setting up on stage with a large number of IEC leads and 240v equipment from 'home' bands. There shouldn't be a situation where a plug carrying double the voltage can be inserted into a piece of incompatible equipment.

I liken it to mis-fuelling a car - filling with diesel instead of petrol (or vice-versa) because here in the UK the nozzles are interchangeable. Many stations also plaster the nozzle with burger ads or whatever which makes them look even more similar. Plus the three or four fuel types share the same dispenser rack. Years ago Diesel was dispensed from a completely separate pump away from the petrol. Mis-fuelling is a big problem here, but easily solved if there was the inclination to do so.

[eschertron]

Maybe if they know it and blatantly ignore it. But we're talking more about safety here, and those kind of issues are never handled in this manner. There is usually some kind of idiot proofing involved, we can't plug regular appliances into clothes dryer outlets.

Here in the US 240 3-phase and 480 3-phase have similar, but not interchangeable plugs and sockets. Similar enough that you have to look at it closely to tell the difference. There's a shop here where I work that builds and tests both 240VAC equipment and 480VAC equipment. I discovered on the last job I did in this shop that they've "standardized" all their plugs to be one type (480VAC) regardless of the voltage requirements of the equipment under development.

Now legally, since 480VAC plugs and wiring are rated for 600V service, it'd be OK to put 240V though it, right? :sheesh:

I haven't blown anything up yet, but the only thing stopping me from applying 480V to machine that expects 240V is my observational acuity. All right, I work here. I won't complain about the utter stupidity of this arrangement.

OTOH, if touring musicians can blow their stuff up on an unfamiliar stage by plugging cord ends into their amps that are - by design - compatible, I'd certainly consider venue management liable for not making different voltage supplies clearly and UNMISTAKEABLY labeled.

[paggerman]

I can imagine some guitarists thinking 'hey, twice as many volts = twice as loud. Gotta try this.' Bang.

I know for a fact that despite knowing that equipment is made for 110v and that local power is 230v a couple of people I know have plugged in anyway. Their loss was my gain