C7/C8 Connector Queries

[Flook]

Hi all,

I’m looking to turn my Skyreach 4 Mini into a brickless build.

It appears the connector will need to be a C8 connector with an accompanying C7 cable. I have been advised that a polarised version of these would be preferable.

Does anyone have experience with these connectors and/or can explain to me the benefits of having a polarised one?

I have searched everywhere online and am unable to find polarised versions, other than by importing them from the US (I am UK based). There is an abundance of unpolarised ones though!

Thanks in advance for your input!

 

[Kmpkt]

C8 polarized and the appropriate cable would be best. The power input on the 160W AC-DC is known as an ELP 2 position and you can get them from most reputable electronic suppliers (mouser, digikey, etc.).

 

[SeñorDonut]

A polarised connector ensures hot and neutral don't get switched. Some low power appliances have circuitry to circumvent this, you can plug it in either orientation like a USB-C connector. I don't know if this is present on the unit you are using though, so it's more like one of those super thin flash drives - physically it fits both ways but electrically only works one way, but in this case it might do a tad more than not work.

 

[Flook]

Thanks for the responses both.

Unfortunately I'm a bit stuck as any C7 polarised cables I find are generally only rated for 125V, when UK mains voltage is ~230V. This is again due to the fact I'd have to import them from the US.

I'm wondering why there would be a shortage of polarised cables/inlets of this type in the UK...

I'm really at a loss for what approach to take now! Perhaps I'll just have to cope with hauling my Dell brick around.

 

[stree]

Have you tried RS or CPC?

 

[Flook]

Have you tried RS or CPC?

Yeah I have. All seem to be unpolarised!

 

[EdZ]

C8 polarized and the appropriate cable would be best. The power input on the 160W AC-DC is known as an ELP 2 position and you can get them from most reputable electronic suppliers (mouser, digikey, etc.).

Are any of the currently available AC-DC supplies actually sensitive to hot/neutral assignment? Most are not due to everything prior to the rectification stage being symmetrical for the live/neutral lines (e.g. same filtering cap layout on each input). Grounding is not an issue unless you use a 'cloverleaf' (C5/C6) plug, and that's already polarised.

 

[stree]

Connector needed is actually C8a
Still not around in UK after an hours google.
A thought.
Use standard male/female C7-C8.........fix a length of square-rectangular plastic bar to the side of the female ( cabled) connector..
Only say 4mmx4mm, cut-file a corresponding notch on the fixed half (C8)......connect cables to 2 halves of connector assembly accordingly...... you then have a one way only fit connector.
Probably what I would do............Also that way, spares are easy too!

 

[stree]

This from "electricians forum UK".author is Bruspark...........eDZ may understand, I don`t!


The other reason polarisation could matter is if there is a metallic part or output on the device. For example many small Switched Mode power supplies for USB charging
or even laptop supplies lack both fixed polarisation and a connected 'E' pin. They both have metallic 'outputs' . They therefore HAVE to output their 5 or 12V DC output pins or whatever floating 'unloaded' somewhere between the two AC input potentials above ground.

Ideally if no 'E' is available the (Neutral) input polarity is mechanically 'fixed' and the designer can then ensure the output/metalwork floats nearer to Neutral which in turn is safely near Ground.



For the reversible C7 type and assemble-able plug/PSU devices this cannot always be guaranteed and so the DC voltage floats between L and N but often it looks more like 80V from one and 150V from another.
The little power supplies that come with TVsticks look like this (and LN polarity of those is reversible according to plug/SMPS assembly). Therefore plugging such a TV stick or a 2 pin Mains powered notebook into the HDMI socket of a grounded AV system can give quite visible sparks that are bigger one way round.



Of course once plugged the AV system easily pulls the high impedance sourced 'floating voltage' down but maybe only after the HDMI board silicon is expensively blown . . If the other equipment is metallic but not grounded we get the 'my phone tingles when it's charging?' effect.



When a supplier says it's not a problem it usually means they know an output is floating 'midway' but the current capability at the float voltage is very low and thus safety compliant (which it probably is and has to be that way in certain other counties where Earth pins are optional and socket polarity a bit variable).

 

[EdZ]

That's a problem that will occur whenever you have a conductive casing, no earth pin, and are not double-insulated. There no no guarantee that Neutral will be anywhere close to ground, an in practice if you are in any situation other than having a single device on that main circuit from the transformer (i.e. you are using a single main device, are the only person in your house, in the only occupied house on that part of the street served by that transformer) Neutral will be for all intents and purposes an inverse of Live.

 

[stree]

I think I understand that.............
As in the ground loop hum in audio equipment, so ground the pre-amp to the amp? ( much simplified for the sake of the comparison, I know ground loop can be a bucket of snakes with many opposing theories?

 

[Choidebu]

Thanks for the responses both.

Unfortunately I'm a bit stuck as any C7 polarised cables I find are generally only rated for 125V, when UK mains voltage is ~230V. This is again due to the fact I'd have to import them from the US.

I'm wondering why there would be a shortage of polarised cables/inlets of this type in the UK...

I'm really at a loss for what approach to take now! Perhaps I'll just have to cope with hauling my Dell brick around.

An unpolarised one would work just as well, you can always change it in the future once you find one in stock.

Edit:
By the way, CMIIW, but these connectors are usually rated for amperage not voltage. Sure, 10.000V vs 250V need different approach (distance and insulation wise), but 125 to 250 is not significant enough to warrant different cables/connectors. Wattage rating, or preferably amperage rating is what you should be looking at here

 

[Thirumal Kumaran]

Necromancing the thread...

I cannot get hold of the polarised C8 connector here.. But even if I do, the cables are always non-polarised (The wall socket end). What is the purpose of it then?
Have anybody tried using a non-polarised connection for HDplex (160 in particular) and have any grounding issues?
or putting it in short, am I going to fry up my motherboard by using a non-polarised connector?

 

[Josh | NFC]

Necromancing the thread...

I cannot get hold of the polarised C8 connector here.. But even if I do, the cables are always non-polarised (The wall socket end). What is the purpose of it then?
Have anybody tried using a non-polarised connection for HDplex (160 in particular) and have any grounding issues?
or putting it in short, am I going to fry up my motherboard by using a non-polarised connector?

Nope.

I'm thinking of changing to a non polarized connector because of all the confusion it has caused. I have the polarized for flexibility in case you were running a 12v brick and wanted to wire the GPU straight off it, like in the G Unique setups.

I think I have another detailed answer on the forum on why I went with polarized (see if you can do a search for it), but the TL;DR is that it doesn't matter for use with the HDPLEX 160/300/

I hope this helps...

Peace

 

[Thirumal Kumaran]

Nope.

I'm thinking of changing to a non polarized connector because of all the confusion it has caused. I have the polarized for flexibility in case you were running a 12v brick and wanted to wire the GPU straight off it, like in the G Unique setups.

I think I have another detailed answer on the forum on why I went with polarized (see if you can do a search for it), but the TL;DR is that it doesn't matter for use with the HDPLEX 160/300/

I hope this helps...

Peace

A very humble request...
Can the next iteration of S4 mini have the C8 cutout enlarged to C6?
As Hdplex 160 moved to 3 wire layout and "forthcoming" 300/350w is going to maintain the same?

Or, Can you please check how the C8 can be enlarged to C6 (The right place to grind / drill) so it helps a lot of concerned guys regarding polarity and grounding issues?