Industrial round plugs (16 A/32 A)

[JohnW2]

At least from wikipedia there seems to be a bit of a gap in the standard for the 5 pin plugs. The yellow is for "57–75/100–130 V" and the blue is for "120–144/208–250 V AC", so there doesn't seem to be any correct plug for 100/173 .

It really makes no sense that they should quote a 'minimum' voltage rating.

On the basis of the (maximum) figures above, the blue would surely be suitable for 110V/173V, wouldn't it?

Kind Regards, John

 

[Simon35]

I suppose there is little/no need in UK/Europe - which I imagine is why all the 4-pin and 5-pin ones I've seen are red.
Do you mean 200V phase-phase - i.e. about 115V phase-neutral?

Kind Regards, John

Yes, 200V p-p

 

[JohnW2]

Yes, 200V p-p

It seems that 'everyone is right', but it seems very odd.

A bit of Googling seems to confirm that most single-phase supplies in Japan are 100V, but that 3-phase is 200V phase-to-phase. Does that mean that, unlike UK (and most other places), single-phase supplies are not derived from 3-phase ones?

Kind Regards, John

 

[ban-all-sheds]

Mennekes make (and sell in the UK) ALL the plugs and sockets you could ever want. There's a 5-pin blue, 5-pin yellow etc, even do a few 3 pin red.

5-pin purple?

 

[AdrianUK]

It seems that 'everyone is right', but it seems very odd.

A bit of Googling seems to confirm that most single-phase supplies in Japan are 100V, but that 3-phase is 200V phase-to-phase. Does that mean that, unlike UK (and most other places), single-phase supplies are not derived from 3-phase ones?

Kind Regards, John

It can still be done...... the secondary of the distribution transformer is arranged in a delta & one of the windings has a center tap which is then earthed to form the neutral. Thus you have 100 - 0 - 100 as well as 200V p-p betweeen the corners. Simples (Just don't connect between the other corner of the triangle & neutral or you'll get 173V)

 

[winston1]

It can still be done...... the secondary of the distribution transformer is arranged in a delta & one of the windings has a center tap which is then earthed to form the neutral. Thus you have 100 - 0 - 100 as well as 200V p-p betweeen the corners. Simples (Just don't connect between the other corner of the triangle & neutral or you'll get 173V)

Ah yes. What the Americans call high leg. Though in their case it comes out at 208v with their 120v supplies.

 

[AdrianUK]

Ah yes. What the Americans call high leg. Though in their case it comes out at 208v with their 120v supplies.

Indeed. The "high leg delta" giving 120V, 208V & 240V all from the same four wires! Crafty!

 

[ban-all-sheds]

Also called bastard leg, I believe

I wonder why?


https://en.wikipedia.org/wiki/High-leg_delta#Disadvantages

 

[JohnW2]

It can still be done...... the secondary of the distribution transformer is arranged in a delta & one of the windings has a center tap which is then earthed to form the neutral. Thus you have 100 - 0 - 100 as well as 200V p-p betweeen the corners. Simples

Ah, cunning - but that can presumably only be used to get two single-phase supplies - i.e. they can't do what we do here and distribute 3-phase around the streets and derive three single-phase (different phase) supplies from it?

Does such an arrangement create an issue as regards 'earthing' if one runs a 3-phase load from it?

Kind Regards, John

 

[plugwash]

It really makes no sense that they should quote a 'minimum' voltage rating.

On the basis of the (maximum) figures above, the blue would surely be suitable for 110V/173V, wouldn't it?

Kind Regards, John

If the rating of plugs and sockets was just about the insulation of the plugs then we wouldn't need so many types. Insulation thickness requirements for "mains voltage" applications are driven more by mechanical robustness concerns than by voltage withstand. I very much doubt there is any significant constructional difference between a yellow plug and a red one.

The point of having different types for different voltages is surely to reduce the risk of someone connecting a device to the wrong supply and either having it not work properly or worse having it go up in smoke.

Unfortunately the 60309 system isn't perfect in that regard, there are gaps between voltage bands and no specific connectors for high-leg systems.

 

[Simon35]

It seems that 'everyone is right', but it seems very odd.

A bit of Googling seems to confirm that most single-phase supplies in Japan are 100V, but that 3-phase is 200V phase-to-phase. Does that mean that, unlike UK (and most other places), single-phase supplies are not derived from 3-phase ones?

Kind Regards, John

Also 50 or 60 Hz depending on where in Japan you are.

 

[mattylad]

I often fit the 32A ones at work and the screw in them are screwdriver killers!

A horrid pair of small cross heads that I cannot get my No2 cross head into (due to the plastic guard surrounding them) and my no1 is too small.
Snapped the end of my straight 4mm screw driver on them.
Grrr...

 

[ban-all-sheds]

Do they have Modulo screws?

https://talk.electricianforum.co.uk/topic/23505-those-mad-mcb-screwdrivers/

 

[JohnW2]

If the rating of plugs and sockets was just about the insulation of the plugs then we wouldn't need so many types. ... The point of having different types for different voltages is surely to reduce the risk of someone connecting a device to the wrong supply and either having it not work properly or worse having it go up in smoke.

I'm sure that's true, and it's obviously about mechanical compatibility (earth pin position) as well as colour.

However, pragmatically, I don't think that really alters the bottom line of what I said - that if, as is the case (and for whatever reason), there are gaps in specified voltage bands, there would be no electrical problem (and not much by way of alternatives) in using one with the 'next higher rating' (just in case there is some difference in voltage withstand etc.). Without thinking too deeply about all the possibilities, I doubt that, within any given country, this would introduce any uncertainty/ambiguity as to what supply voltage the plug was intended to be connected to.

The gaps in the 60309 voltage bands seem to have been the result of a fairly major 'oversight' - none of them appear to include a phase-to-phase voltage anywhere near 173V - as you have said, there is a 'gap' between 130V and 208V.

Kind Regards, John

 

[JohnW2]

The gaps in the 60309 voltage bands seem to have been the result of a fairly major 'oversight' - none of them appear to include a phase-to-phase voltage anywhere near 173V - as you have said, there is a 'gap' between 130V and 208V.

I'm not sure under what circumstances one is 'allowed' to invoke an IEC 60309 "variant", but ....

Kind Regards, John