Ribbon cable current rating

I'm about to purchase some ribbon cable from ebay for use on a mendel90 I'm currently building. The cable is a 40 way cable (as is it the cheapest option- which i will then split to the correct size), however, each strand is rated to 300V 1A, is this enough to be used on a mendel90 or should i think about purchasing one with a higher current rating.
Also, if anyone had any alternative places to purchase ribbon cable cheaply (in the UK) please could you tell me.
Thanks

That sounds low to me. The pcb is 0.8 ohms so draws 15 amps at 12 volts.

Ralph Hilton Wrote:
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> That sounds low to me. The pcb is 0.8 ohms so
> draws 15 amps at 12 volts.

I doubt that ZhangX will be using a single strand to draw current for the bed and without knowing how many strands are involved for the bed current in this set up, we cannot really comment.

The grey ribbon cable used by Nophead in the Dibond kits is bog-standard IDC ribbon cable - I cannot recall the current rating but the key point is how many of its conductors are set in parallel for the high current loads.

Alan

Edited 1 time(s). Last edit at 07/29/2013 12:07PM by Alzibiff.

The dibond kit uses a 26 way ribbon cable. With two wires used for the bed thermistor that leaves 12 for the PCB 12V and GND. You could use a 40 way cable to get 19 wires for the PCB but you'd need wider clamps and new holes for them in the dibond sheets - unless you're not using the kit in which case you're free to drill holes wherever you like in whatever material you're using...

Edited 1 time(s). Last edit at 07/29/2013 12:17PM by QuackingPlums.

Alzibiff Wrote:

> I doubt that ZhangX will be using a single strand
> to draw current for the bed and without knowing
> how many strands are involved for the bed current
> in this set up, we cannot really comment.

12 in the standard kit. so awg 26 should be fine.

Also the correct bed resistance for a Prusa MK2 bed is 1.2R, not 0.8R.

I buy ribbon cable from Rapid Electronics.

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[www.hydraraptor.blogspot.com]

[reprap.org]. The author said his was 0.8 ohm.
Mine measures 1.0 ohms at the electronics board end.

There are multiple authors of that page. The one that said 0.8 was evilB and he said it blew up his RAMPS board! Some sellers make the mistake of getting plated through holes and that causes all the tracks to be plated as well making the resistance too low.

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[www.hydraraptor.blogspot.com]

Whoops!. Anyway the ribbon cable you supplied doesn't even get warm so if that is awg 28 then I guess the OP won't have a problem using 12 + 12 for the heater.

QuackingPlums Wrote:
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> The dibond kit uses a 26 way ribbon cable. With
> two wires used for the bed thermistor that leaves
> 12 for the PCB 12V and GND. You could use a 40 way
> cable to get 19 wires for the PCB but you'd need
> wider clamps and new holes for them in the dibond
> sheets - unless you're not using the kit in which
> case you're free to drill holes wherever you like
> in whatever material you're using...

I'm self sourcing a mendel90 to build with plywood (I can get hold of it with relative ease).
I would prefer not to use the whole 40 cable as I imagine that it may be a tad too wide to look at/ route carefully.

On the RAMPS 1.4 wiring schematic (the electronics i'm using) it says that the bed uses 11A of current, therefore would it be safe if i just used the standard 26 way setup with 12 to + and 12 to GND, as it should give me and overall 12A rating??

It doesn't matter what it says on the RAMPS. It is the bed resistance that determines the current. Standard beds take 10A and 12 wires are fine. If you have a bed with a lower resistance you might need more.

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[www.hydraraptor.blogspot.com]