Using Power Cables as Control Cables

I think there shall be no problem of using power cable of 2 x 2.5mm2 for controlling your system where same size of control cable will be required. But power cables are more rugged designed considering staring loads and other factors,- so they are costlier than control cables. If your cost permits then you can use it.

You can also superimpose a control signal on the line and later just split it again.

Note that the signal don't pass through a transformer.

In terms of control circuit, it is not a problem to use this size of cable but it may be the problem in terms of power circuit. For use it in power circuit, make sure

(1) The cable is properly sized for the load with all other derating factors are in consideration (ambient temperature, cable raceway, voltage drop etc.).

(2) The local standard allows to use this size for power circuits. Most standards regulate a minimum size for a cable to be used in power circuit, verify with your local standard. In most cases, 2.5 mm2 is the minimum size that is allowed for power cable.

If both (1) and (2) are satisfied, there is no problem to use this cable for power circuit as well.

See previous thread http://cr4.globalspec.com/thread/51680 for detail about the different category of cables.

- MS

Wow, I'm very happy there are a lot of participants responding my question. My question appear after seeing cable catalogue. On the catalogue there is different sheet between Power Cable and Control Cable with the same specification (N2XFGbY, 2C-2.5mm2, 0.6/1kV, Cu,XLPE/GSWA/PVC). So that's why I become hang in doubt and worry about that (Because We had bought the cable, I worry the cable can't be used as control cable. Hehehehe...).

I still have another question. As far as I know, there is minimum distance (clearance) between power cable with instrument cable. What about Power cable with Control Cable? Can power cable and control cable have no separation (Without clearance), or pulling in the same conduit ? Because if I see from the specification, the voltage of both cable are the same (0.6/1kV). But I still doubt because of the function (As power and as control).

Hope participants can give great explanation.

Thanks a lot for all participants ....

^_^

Hi

As my knowledge there should me mininum of 500mm distance gap inbtween power cable and control cable, otherwise induction voltage will come in control cables.

This is the first time I am posting in this

Hello,

There is no problem to put the power and control cables together.

WRONG- there is a major problem putting control cables in the same conduit, or in the same cable tray, as power wiring.

The magnetic flux field created by power cables can even overcome shielding of control cables if there is enough electrical energy going through the power cables. This flux can trigger false signals or scramble a signal into electronic mush.

Alaways try not to run control cables in same conduit or tray where there is a power cable. The flux developed by power cable is not only due to voltage but also due to high Curent flowing through the power cable and This flux can trigger false signals or scramble a signal into the operating system to create mal operation.

A minimum gap of 500mm should be maintained if it is unavoidable to run the control cables through a separate cable tray.

Control Cables

Control Cables differ from Power Cables in their application, they are used to carry control signal of low power strength, but can be subjected to severe working temperature conditions like heaters, boilers and can be exposed to oil, chemicals and other solvents.

L.V. PVC INSULATED UNARMOURED OR ROUND WIRE/FLAT STRIP ARMOURED CONTROL CABLES UPTO & INCLUDING 1.1 KV
VOLTAGE :- These cables can be used on AC Voltage up to & including 1100 V or DC up to & including 1500 V.
Size :- 1.5 Sq. mm. & 2.5 Sq. mm. up to 61 Cores in Control Cable.
CONDUCTOR :- Annealed Bare Electrolytic Copper / Aluminum Conductor conforming to IS:8130:1984.
INSULATION :- Conductor are insulated with PVC Compound as per IS:5831:1984.
COLOR OF CORES :- Cores are identified with a color scheme as per IS:1554(Pt-I):1988 as under
2 Cores - Red & Black
3 Cores - Red, Yellow & Blue.
3 ½ & 4 Core - Red, Yellow, Blue & Black. (Reduced Neutral Core in case of 3 ½ Core)
In case of cable exceeding five cores, two adjacent (counting and direction cores ) in each layer shall be colored Blue, Yellow and remaining cores gray/Cores can be identified by numbers by numbers printed on that of same color .
LAYING Of CORES :-Cores are laid up with a suitable lay. The Final layer direction shall be kept right hand lay.
INNER SHEATH :-The Inner Sheath is applied over laid up of cores by extrusion/wrapping of thermoplastic material.
ARMOURING :- It is applied over inner Sheath. It may consist of galvanized Round Steel wires or galvanized Flat Steel Strips conforming to IS:3975. Round Wire armoring is provided , where the calculated diameter under Armour is 13.0 mm. Above this, armoring is either round wire/steel strip.
OUTER SHEATH :-A final covering of PVC Compound, conforming to IS:5831:84, is applied over Armoring in case of Armored Cable or over Inner Sheath in case of Unarmored Cable, called as "Outer Sheath".
The Insulation, Inner Sheath & outer sheath can be HR PVC, FRLS PVC or FRHF Compound depending upon their application.
CURRENT RATING :- e.g. Current Carrying Capacity of these cables are as per IS:3961{Pt-II) : 1967.
QUALITY ASSURANCE :- Quality Standards are built in every Relemac Technologies India's product. Relemac Technologies India cables are subjected to a series of required tests in our well equipped laboratory . Besides the rigid tests and checks at every stage from raw material through manufacturing stages and finally up to the finished product .
TYPICAL APPLICATION :- Control cables are used in industrial power or control circuits for conveying electrical signals to the associated devices. These cables are suitable for installation in cable trays,Cable Ducts,Conduits or underground buries, raceways, and outdoor locations in under mechanical stresses in Power & Switching stations and relays, local distribution systems, industrial plants, commercial buildings, refineries & chemical plants etc.

Hendrix's post (#2) is right on. You will need a Power Line Carrier (Also called a PLC, but NOT the smart box) and whatever number of control modules as determined. The system will operate exactly like a hard-wired control package.

Not sure who makes these currently, but a Google search should tell you.

You should register. It helps us know who (and where) you are so that our answers can be better focused on whatever your specific issues might be.

Plus- when / if you answer someone else's post, you can get "credit".

Wow, so much misinformation.

Copper is copper is copper is copper.

The difference between ANY two types of cables is just the insulation and possibly shielding (screening).

In the description you have given, there appears to be absolutely no difference.

Power cable: N2XFGbY, 2C-2.5mm2, 0.6/1kV, Cu,XLPE/GSWA/PVC.

Power cable: N2XFGbY, 2C-2.5mm2, 0.6/1kV, Cu,XLPE/GSWA/PVC.

The frst string of digits appear to be the reference number of the cable.

The middle string of digits denoted the number of conductors, size and insulation voltage rating, followed by Cu to denote copper.

The final string of digits states the insulation (XLPE = Cross Linked Polyethylene, GSWA = Galvanized Steel Wire Armored, PVC = Poly Vinyl Chloride plastic overall jacket), meaning it is a pair of 2.5mm² conductors with XLPE insulation, surrounded by a steel wire armor mesh, covered by a PVC jacket. What you do with it, whether control or power, is totally up to you and that determines what you call it.

It's very common, at least here in the US, for there to be requirements that all conductors used in a common raceway have the same insulation value as the highest available voltage. So if you have control signals and power wiring run together, and the power wiring is at a 1000V potential, then any control wiring in the same raceway would be required to also have 1000V insulation. So it's not uncommon at all for someone to specify the same cable if all you need is two control conductors and two power conductors.

A1) Yes, evidently, as the answer is already in the question: the cable is specified as an incoming condition of acceptance from somewhere else.

Whether it is the best choice is another question and the answer might be at variance with that specification.