We need to get lugs 50 for power cable with PVC insulation 4*50. The lugs ТМЛ 50-10-11 are too big. Please recommend a solution.

There are several ways to solve your problem:
You can order lugs manufactured in accordance with DIN 46235, for example, it can be ТМЛ 50-10 made by KBT.
The best choice is the standard ТМЛс 50-10 made by KBT. They are made exactly for the cross-section that is indicated in their name.

Or you can use lugs with index 35 mm² that are made in accordance with Russian standard ГОСТ. They will be ideal in your situation. There is a special chart in this standard that recommends using lugs 35 mm² in your situation.

Can a ПМ lug designed for soldering be crimped?

Yes, of course. With progress and more attention to environmental care crimping became preferable to soldering. These type of lugs has all necessary things to be crimped- the seam is welded. However, it is important to remember that ПМ copper cable lugs are not designed for crimping of solid wire, they can be used only for stranded wires with flexibility class from 2 to 6.
The inner diameter is of 6th class of flexibility, so it is better to use a V-shape die for crimping. Use CTB-05 and CTK 05, ПК 16 and ПК 35 for small cross-sections from 1.5 to 10 mm² use ПМУ-120, ПМУ-240 or hydraulic ПРГс-240 for bigger lugs. The ideal combination is a set of dies НМ300-ПМ with one of the hydraulic crimpers: ПГР-300, ПГРс-300 or ПГП-300 made by KBT.

How can I connect copper and alum cables?

We have special bimetallic cable ferrules for connection of copper and alum cables. They are called ГАМ. The copper and alum part in these ferrules are connected by means of friction welding.

What is the difference between the Russian standard ГОСТ and DIN?

The difference is as follows:

- DIN lugs have a longer barrel
- The inner diameter of DIN lug is of the 2-3d class of flexibility, ГОСТ lugs have an inner diameter of 6th class of flexibility. So the inner diameter of ГОСТ lugs is bigger than of DIN lugs.
- ГОСТ lugs with small cross-sections have a thicker wall of the barrel than DIN lugs and ГОСТ lugs with big cross-sections have a thinner wall of the barrel than DIN lugs. We reckon that the thickness of the wall is calculated the best in DIN 46235.
- DIN lugs have special markings about the place of crimping and quantity f crimpings.
- The size of the palm of ГОСТ lugs does not depend on the diameter of the hole. The size of the palm of DIN lugs is made in accordance with the diameter of the fixation hole.

What is the correct method to crimp alum lugs and ferrules?

Work with alum cable has some specific peculiarities. Alum surfaces are subjective to air influence and they get acidized in few minutes. This acidized layer on the surface is of very low electrical conductivity. That is why it is important to rough up the wire with a wire brush and apply silica-vaseline paste immediately after removing of insulation from the cable. If the wire is of triangle-shape, it should be rounded by crimping with dies НМ-300-C made by KBT. The inner surface of a ferrule should also be treated with silica-vaseline paste. It is important to remember to use as little time as possible to complete the crimping to avoid any acetifying of the alum wire.

What is the difference between copper marine ferrules and common copper ferrules?

Marine copper ferrules are two times longer in size, so they need two times more crimpings. Marine ferrules should ensure extra mechanical strength required in marine applications.

Why bimetallic lugs ТАМ made by KBT are more expensive than common alum lugs with copper сoating?

The technology of gas-dynamic spraying was applied by Russian scientists from Novosibirsk in the 80s of the 20th century. This technology has proved to be effective and cost-efficient. In the 90s other scientists from Novokuznetsk adapted the technology for cable lugs, and it was also efficient at the beginning. However, we all know that sometimes striving for expenses reduce provokes uselessness of the initial idea: in reality, the copper coating was so thin that it could not survive even single-use and got sometimes broken even after minimal mechanical action. As a result, such cable lugs could not be reliable at all and occurred to be as dangerous as a delay-action bomb. That is why KBT took a decision not to deal with the production of alum lugs with a copper coating, but introduced bimetallic lugs on the market. These kind of lugs are reliable as a relatively thick copper sleeve is pressed to the alum frame of the lug.

How can I choose a correct lug for the cable? What are the aspects to be taken into account?

The correct choice of the lug is very important as the reliability of the connection depends on it. The golden rule for this is- inner diameter of the barrel should match the diameter of the core prepared for crimping. It means that there be almost no gap between the lug and the wire. It is quite easy for lugs like ТА, ТАМ, ТМЛ(DIN), ТМЛс, НШП as the nominal size of each corresponds to the cross-section of the core. It gets a little more complicated when you deal with ТМ and ТМЛ (Russian standard ГОСТ 7386-80). You can use s special chart give in the correspondent ГОСТ standard. However, in this case, you should definitely know the flexibility class of the cable core. This info is usually no problem is you know the type of cable you deal with.
In the ideal situation, you should measure the core diameter and match it with a diameter of the lug barrel indicated in the chart of ТМ\ТМЛ made by KBT. The third figure in the name means the necessary diameter, for example, ТМЛ 70-10-13. The last figure, 13 in the example, should be very close to the diameter of the core, but not less!

How many times should the lugs and ferrules be crimped?

The quantity of crimpings depends on the length of the lug barrel, as well as on the width and type of the dies used for the crimping. A couple of crimpings is enough for V-shape dies. More crimpings are needed when you use narrow hex dies (5mm). Wide hex dies require 1 or two crimpings depending on the size of the lug. You can find a special chart on our website, that contains information about the number of crimpings in each particular case. It worth saying also that DIN 46235 lugs have a special indication for narrow and wide dies.

What is better- a V-shape or a hex crimping?

The crimping can be reliable only if you carefully matched the inner diameter of the core and inner diameter of the lug barrel.
Hex connection has positive mechanical strength and ensures a bigger area for electrical contact between the core and the lug. If you have chosen the sizes correctly, the connection is almost leak-proof, does not damage separate cores, it looks good as repeats the shapes of the cable shape.
V-shape crimping is useful when the inner diameter of the lug barrel is bigger than the diameter of the core. Moreover, it is better to crimp solid wire with a V-shape die.
V-shape dies can be called universal as they can crimp lugs in almost all type and size, using the tools ПМУ-120 or ПМУ-240 made by KBT.