Narva 7 pin Flat Plug and Brake Controller

[Throbbinhood]

Thanks bigguwesty. I'll try with some smaller cable and see how I go. Thanks all.

[Cuppa]

I'll try with some smaller cable and see how I go.

I'd suggest that you contact the brake controller manufacturer or an auto electrician & as their advice about cable size in mm2. The electric brake actuators at the wheels will require a minimum voltage & if the cable is too thin you *may* not get this because of voltage drop. The specification of the wire in amps by the brake controller manufacturer is to ensure the cable is thick enough to ensure you dont get too much voltage drop, not because it needs to carry 20 amps.

This may help. https://www.couplemate.com.au/carava...ic-brakes-faq/ Note that the measurements are in Sq.mm of copper. Autocable sizing is misleading as it includes the insulation as well as the copper, so if for example you need 4mm2 & bought 4mm autocable, your cable would be inadequate.

I'd suggest that that '25 amp' jaycar cable is too thin.

As has been suggested already 6mm cable (auto cable) is a fairly safe bet. Many caravanners get around the connecting it to the 7/12 pin socket problem by 'bypassing' the socket altogether, & instead using an Anderson connector for the brake controller cable.

[Throbbinhood]

I'd suggest that you contact the brake controller manufacturer or an auto electrician & as their advice about cable size in mm2. The electric brake actuators at the wheels will require a minimum voltage & if the cable is too thin you *may* not get this because of voltage drop. The specification of the wire in amps by the brake controller manufacturer is to ensure the cable is thick enough to ensure you dont get too much voltage drop, not because it needs to carry 20 amps.

This may help. https://www.couplemate.com.au/carava...ic-brakes-faq/ Note that the measurements are in Sq.mm of copper. Autocable sizing is misleading as it includes the insulation as well as the copper, so if for example you need 4mm2 & bought 4mm autocable, your cable would be inadequate.

I'd suggest that that '25 amp' jaycar cable is too thin.

As has been suggested already 6mm cable (auto cable) is a fairly safe bet. Many caravanners get around the connecting it to the 7/12 pin socket problem by 'bypassing' the socket altogether, & instead using an Anderson connector for the brake controller cable.

Well the Jaycar cable appears spot on the thickness that the brake controller is supplied with, if not fractionally bigger.

Why would the jaycar cable be too thin, if it's rated at the correct amp rating (actually over by 5amps).

[Cuppa]

Well the Jaycar cable appears spot on the thickness that the brake controller is supplied with, if not fractionally bigger.

Why would the jaycar cable be too thin, if it's rated at the correct amp rating (actually over by 5amps).

The specification of the wire in amps by the brake controller manufacturer is to ensure the cable is thick enough to ensure you dont get too much voltage drop, not because it needs to carry 20 amps.

Read the article I found for you. You will see that the actual current draw of the brakes is significantly less than the capability of the wire. It's current carrying capacity in this instance is an irrelevant red herring. Stop thinking about 'Amp rated' cable, & instead think in terms of the amount of copper - in mm2. You will see that 3mm2 may be ok depending upon whether the two wheels are wired in series or in parallel. I suggested 6mm autocable (which is actually about 4.5 or 4.6mm2 copper) because this would work in either configuration. That Jaycar cable is only 2.9mm2 - Brakes are important & cable being slightly undersized at 12v could be the difference between effective & ineffective brakes. Over time a bit of oxidation on the connectors can easily increase resistance, resulting in even greater voltage drop, so using 2.9mm2 cable which is marginal at best in this application is not really conducive to long term reliability even if it is sufficient at the outset.

[mudski]

FWIW. I have the same controller and are just using the standard 4mm 7core wire for the lot and have been for the past 2 years with no issues.

[JME_GU]

I have recently wired up a Red Arc brake controller and went through the same dramas. I used a trailer socket from Super Cheap Auto that was made of metal and included test LEDs in it to make wiring really easy, it handled the 25A wiring easily.

I'm no electrical engineer, but if the manufacturer has specified 25A then that it what I installed. According to the manufacturer, 25A wiring is able to support up to triple axle braked trailers, more than I will ever need.

[Throbbinhood]

I used a trailer socket from Super Cheap Auto that was made of metal and included test LEDs

Was it a flat plug by chance? Really hoping to stick with a flat plug.

[GeeYou8]

I have got the Redarc controller, The cable I used just fitted in the genuine Nissan socket, I can't remember the actual size.
The problem I have is that the contacts are obviously not that good, I have to clean the contacts almost every time I connect (blue light flickers off)
I will have to look at the 12 pin set up.
Trailer is tandem axle car trailer with brakes on one axle.
Graham

[johno90]

As cuppa mentioned dont get trapped into mm vs mm2, there is many different ways to measure a cable, but as suggest 6mm auto cable is what id run, 90% of 7 pin sockets ive used have fit this, maybe yours is an odd one and have a look at a different brand socket but still std 7 pin

[johno90]

Imo your using cable too big..
A bit of 3mm wire is all you need..
It's what they use on the hubs so can't see why you need bigger for the bit between lol..

I was going to suggest the 12 pin flat as they have 5 larger pins as you mentioned. But imo that's for fridge and battery power..
12 pin is also handy if you wish to have a reverse camera on the van..

They use 3mm on each hub which yes is fine for that hub. Then 2x hubs plus distance. All this calls for a bigger size cable.

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