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24V gate - what size cables for 25m in duct run?


readiescards

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Where is the control box going ..?? Normally you need to put the box with the gates as not only do you have to run the motors you will need sensor wires etc for the beams, key fobs etc. 

 

To answer the wire question though - 4mm2 would be a 2% voltage drop for 7A at 25m

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So there will be a wire per gate as they are normally separate plus at least a wire to a beam sensor, and depending on the unit there may also be a flashing light to show it’s opening or closing. 

 

This is all normally in an IP65 box at the gate with just a single power wire. There may then just be a single control wire to an intercom 

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I might be wrong but that looks like the spec for the gate motors not the control panel psu. As Peter has said the control panel would normally be located close to the gates to allow the various sensor circuits, gate motors and indicators to be connected to the panel. 

The control panels I researched were all 240v with a transformer to step the motor voltages down to 24v. 

 

Remember to add add provision for communication from the house to the gate. I.e. voice and/or video access. Normally CAT5/6 is sufficient.

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This I think is the opener manual:

 

idv0532a01en.pdf

 

Says on page 3 of the above that the MC824H control panel is compatible with the 36W LFAB4024 and the XLFAB5024 50W. And here's the manual for that:

 

D00011568.pdf

 

The control panel still needs 230V AC to it even though the motors are 24V DC I think you'll find. All the cable sizes / run lengths are in the manual on page 2 of the second manual.

 

 

 

 

 

 

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You really don't want to be running 24V that length. If you do it's no use applying the voltage drop calculations for 240V.  A 10V drop may be allowable for 240V but would be catastrophic for a 24V system, so you would end up with a monster sized cable.

 

Stick to 240V and put the control box close to the gates.

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25 minutes ago, readiescards said:

Darn was hoping could use 24v from the house to save digging up my duct to repair it for 240v. 

 

These automatic gates getting tedious, think I might tell my partner she'll have to open/shut them manually instead

 

Thanks all

Why do you need to dig it up ? Isn't it cheaper and easier to pull a HO5 or HO7 cable through and leave it submerged? Just a 2.5mm2 3.core flex then with an cat6 for comms / accessory switching. 

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Imho any underground duct might be subject to condensation internally, more so if the cables run a bit warm. This could conceivably pool at any low point in the duct and affect and cable laying in it. I imagine this is one reason why any cable in a duct should be "duct rated". 

 

Paranoia? The regs touch on the issue of condensation, protection against moisture etc. The last bit of duct I ran I even considered running a length of aquarium tube in there so I could periodically pump out whatever, if anything, got in there. I even considered punching some drain holes mid point in the duct, wrapping in landscape fabric and packing gravel around it before concreting. Of course then I worried about the water table etc so in the end did nothing! :)

 

I just ran everything in 20mm conduit and kept those together with some black dowpipe for neatness when concreting. 

 

SAM_8617

 

Just noted that photo was taken in June 2014 @readiescards and it's still not finished! Tell your missus  :)

 

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Spec

 

APPLICATIONS OVERVIEW

Our H07RN-F is a heavy-duty rubber flexible trailing cable for power supply with a voltage rating of 450/750V designed to provide high flexibility and to withstand chemical, mechanical and thermal stresses. It is suitable for applications such as handling equipment, mobile power supplies, worksites, stage and audio visual equipment, port areas and dams. As part of Eland Cables' portfolio of rubber flexible cables, the tough rubber sheath also makes this cable suitable for use in drainage and water treatment, cold or refrigerated environments, and severe industrial environments.

 

And yes, he is paranoid :D

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