About Cable Drums
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What is a cable drum?
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How does a cable reel work?
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What must be taken into account when selecting a cable reel?
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Why do you have to unroll a cable reel?
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What special functions are available for cable drums?
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Which cable drum is required for camping?
What is a cable drum?
A cable reel or cable reel or cable reel is used to save space on electrical cables. Depending on the application, the number of wires, wire cross-section and sheath material can be very different for the wound-up cables. In addition, the types of plug connections can also vary considerably.
Due to its design, a cable reel is a variable extension cable that can be easily set up and unwound by rotating the drum. When wound up, the extension cable takes up very little space. Long and heavy extension cables can also be easily transported without the cables becoming entangled or entangled.
Even though there are cable reels for network or telephone cables, most people think a power or power extension cable is used when talking about a cable reel.
If previously preferably sheet steel cable drums were offered, plastic cable drums made of durable special plastic are now becoming increasingly used. Only the stand is still made of light metal on most of the models.
How does a cable reel work?
Anyone who has already wound up a mains extension cable over the forearm knows the phenomenon: The next time the power line develops an apparently unbelievable self-life and throws one loop after the other.
The reason for this is that the power cable is not unwound cleanly, but the cable loops are pulled apart sideways. This causes the cable to be twisted one time in length per loop. Wrapping an already twisted cable increases the effect the next time you pull it apart.
This is exactly what a cable reel does not do. When the cable is rolled up, it is placed around the drum in a circular pattern. Since the cable is not twisted during unwinding, it remains as flat as before unwinding.
Other advantages:
Variable extension cable
Only as much cable needs to be unwound as you need. Provided that no high-performance consumers are operated.
Integrated multiple socket
Many cable drums offer several, sometimes also different, sockets for connecting the consumers.
Most cable reels are built into the rotating drum body. A mains plug is attached to the cable, which must be connected to a mains socket of the domestic installation. In this case, the cable reel is always at the place of use.
A cable drum for wall mounting, on the other hand, is mounted near a mains socket. Only the cable with an earthing contact coupler is pulled to the place of use.
What must be taken into account when selecting a cable reel?
When selecting the correct cable reel, it is not just the price that should be decided. There are far more important selection criteria that are relevant to the purchase decision.
CEE, CEE-Cara or earthing contact
The most important decision criterion is the connection plug (connection A in our technical data).
A cable reel with a CEE plug for three-phase current does not make sense if only a grounded socket is available as a voltage source. On the other hand, a safety plug does not help, if a CEE-Cara connection is needed for camping and caravan.
The sockets on the cable reel (connection B in our technical data) are in most cases identical to the connection plug (connection A).
However, there are also cable drums, which also serve as plug adapters and provide different sockets.
CEE-Cable reel
CEE-Cara-cable drums
Earthing contact cable drums
Indoor or outdoor use
Next, it must be clarified whether the cable drum is used indoors or outdoors ( IP44 required ).
Of course, an indoor cable reel without special weather protection will also work outdoors for the power supply of an electric lawn mower. At least as long as the power supply is only mowed when it is dry and then the flexible power supply is removed again. In this case, the least hobby gardeners will have problems.
However, due to the missing socket covers (protection against contact or penetration of foreign bodies) and the possibly defective UV resistance, an outdoor use is not recommended. However, at the latest when the cable reel is exposed to moisture and rain, a splash-proof specimen with IP44 or higher must be installed.
Cable type
The technical data often also specifies the cable type with number of wires and cross-section. A combination of letters and numbers provides precise information on the structure and mechanical load capacity of the power line used, if required. Here are some examples:
H07RN-F 5G1.5 (flexible rubber hose cable with 5 wires a` 1.5 mm²)
H05RR-F 3G2.5 (flexible rubber hose cable with 3 wires a` 2.5 mm²)
H07BQ-F 5G2.5 (flexible PUR hose cable with 5 wires a` 2.5 mm²)
H05VV-F 3G1.5 (Flexible plastic hose cable with 3 wires a` 1.5 mm²)
AT–N07V3V3–F 3G2.5 (flexible plastic hose cable with 3 wires a` 2.5 mm²)
Breakdown of cable designations:
H = Europe-wide harmonized labeling
AT-N = National labeling
05 = withstand voltage 300 V / 500 V (L1 to ground / L1 to L2)
07 = withstand voltage 450 V / 700 V (L1 to ground / L1 to L2)
First letter after the dielectric strength =material of the wire insulation.
Second letter after the dielectric strength = material of the sheath.
R = Ethylene propylene rubber
N = Polychlorpropylene rubber
B = Ethylene propylene rubber
Q = Polyurethane
V = PVC; V3 = PVC, cold resistant to -25°C.
F = the copper cable is finely stranded, so that the cable is flexible.
Note:
However, the type designation of cables is much more extensive. If necessary, the Internet helps to classify other cable types.
Recommendation:
PVC hose lines are sufficient for occasional use at home. For continuous use on construction sites or in workshops, a construction site cable drum or professional cable drum with a robust construction site or rubber hose line is the better choice. Even if the price is higher.
Cable length
Select the cable length of your new cable drum so that the cable is just sufficient for all applications.
It is not necessary to calculate a "reserve length".
If an extension cable with a maximum length of 20 m is perfectly sufficient to reach every point on the property, you should also opt for a cable reel with a cable length of 20 m.
A 40 meter cable wouldn't make much sense. However, the extra weight, which must be constantly carried along, does not necessarily give the decisive effect.
Rather, it makes a big difference whether only 5 m or 25 m excess cable has to be unwound from the drum and then rolled back.
Why do you have to unroll a cable reel?
The yellow arrow marks the fuse that can be switched on again.
Long lines are not always the best solution. At least not for cable drums.
The longer the cable, the higher the cable resistance. And the higher the line resistance, the greater the power loss and heat generation.
When wound up, the inner cable windings have no chance of dissipating the heat generated to the outside. For this reason, a cable reel must always be wound to its complete length when high-performance consumers are connected and operated for a longer period of time.
For safety, many manufacturers install resettable bimetal thermal fuses in their cable drums to effectively prevent overheating of a cable that has not been completely unwound.
Practical tips
In a Christmas market or a street festival, only economical LED lighting is often connected to a cable reel. Even if due to the low current it would not be necessary to completely unwind the power line, the cable should still be unwound completely.
Experience has shown that the free sockets lead to further extension cables and distributions being connected without thought. Suddenly, three fryers, a refrigerator or two electric heaters hang on the cable reel without you noticing it.
What special functions are available for cable drums?
The requirements for cable drums are extremely high, especially in the company's use on construction sites. Robust cables with thick rubber coating stand up to the tough conditions as well as a solid drum made of special plastic and protection class IP44. In addition, some models are still equipped with useful special functions:
PRCD S
The abbreviation PRCD stands for P ortable R esidual C current D evice and corresponds to a mobile residual current protective device with protective conductor detection and protective conductor monitoring (-S).
If an insulation damage occurs with a connected consumer and a residual current flows, the power supply is switched off immediately. In the event of damage, life can be saved. Especially when the PRSD-S cable reel is connected to a socket without or with a faulty residual current fuse (FI).
Rotary contacts
Often, a cable drum still has to uncoil a few meters of cables because the location changes or the unwound cable is in the way. If the drum is already connected to a drill, jigsaw or grinding device, the most beautiful cable mess is available through the rotating sockets. Even if only one machine is connected, the supply line is strongly twisted.
The problem has already been recognized by the manufacturer and has also been solved brilliantly. Thanks to a clever rotary contact mechanism, the drum sockets do not rotate when the cable is wound or unwound.
Spring-loaded
Simply roll up the cable by pressing a button. What is common in vacuum cleaners has also been used in cable reels. When the cable is pulled out, a spiral spring is clamped, which then brings the cable back into the plastic cable box at the push of a button.
The retractor has proved particularly useful for stationary cable drums, where only the cable with the earthing contact coupling is pulled to the place of use.
Which cable drum is required for camping?
The left cable reel for the campsite, the right one for home.
CEE-Cara connectors are used for power supply in the caravan and camping area.
Like earthing contact plugs, CEE Cara plugs are three-pole and designed for 230 V/16 A.
If the caravan at the campsite has to be parked further away from the next power connection, a cable reel is required, which has a CEE caravan plug and a CEE caravan coupler (see left cable reel).
If the caravan is to be supplied with power at home, the cable reel must have an earthing contact plug and a CEE caravan coupler (see right cable reel)