Went to the BICC (British Insulated Callenders Cable ) factory where they extruded the cable to the finished product, probably the most fascinating day out I have had in a long while. Because they use the same insulation color coding and crimping tools as spade terminals, butt-splice connectors (Figure 5) often appear in the same manufacturer’s series as spade terminals. As acceptance engineer I felt I should be able to terminate the MICC myself if I was going to downgrade or condemn an installation.

Let me make a disclosure here: I once worked for a large German connector company, and my current employer is a spin-off that maintains close “connections” with said company. I documented tidbits that I gleaned on connectors working on several projects in the industrial sphere over the years in two blogs: “ Which PCB Connectors Are Best?” and “ Unusual connectors.” The point is that this kind of exposure may possibly limit my knowledge as to all of the different ways there are to connect two (or more) ends of wire. Based on this, I hope that other members of the EEWeb Community will add their suggestions in the comments below.

Click & Collect

I also quite like the single ended screw connectors that are a cross between eurostrip and wire nuts: Figure 4: A floating blade terminal. The color of the insulation indicates the wire gauge to be used. There are many variations of insulation, from none to completely covered. There are also many manufacturers. This is a Panduit DNF14-250FIM-M. (Source: Digi-Key online catalog) Eurostrip– we also used to call it “Chocolate strip” even though it was made of soft plastic and could not be snapped. I thought it was from the segmented appearance. The bare cable end needs to be straight. Wago pushfit connectors are half the size per way of lever connectors. Pushfit can't use stranded wire. Ashley make pushfit junction boxes with cordgrips.

It makes me wonder where you live, and whether the electricians are working to the local codes (regulations)?” British regulations even make a distinction between maintained and non maintained junction boxes and connections, Which is why I always use the Wago connectors now no screws to come loose.Spring clamp terminals use a spring-operated clamping mechanism to hold the conductor in place. A screwdriver is inserted into the terminal, the wire is inserted and when the clamp is released it holds the wire in place. These types of terminals are very secure and ideal in environments subject to high vibration. Push-in connection

The aforementioned butt-splice connection is forever. However, there is a cross between the butt-splice and flying blade approaches that is often referred to as a “bullet” connection (Figure 6).Figure 3: A spade terminal. The color of the insulation indicates the wire gauge to be used. There are many variations of insulation, from none to completely covered. There are also many manufacturers. This is a Panduit DNF18-250-M. (Source: Digi-Key online catalog) This connector has two channels. You slide the main wire along one channel and the tap (unstripped) into the second channel and close the assembly. It may require a pair of pliers to force a metal blade through the insulation of both wires (this technique is known as insulation displacement technology, or IDT) that remains in position, shorting the cables together. Butt-splice connectors with IDT Small diameter flexes and some cordgrip designs result in the plug cordgrip failing to grip the flex. This can be remedied by putting the flex 360 degrees round the cordgrip before tightening, like so: Grounding screws are often color-coded green and, when used on consumer electronics, often have a washer with gripping "teeth", to ensure better connections. However, with the clamping plate type of screw terminal this time is reduced, since it is necessary only to insert the stripped wire between the terminal and the rear clamping plate then tighten the connection, using the screw to clamp the wire between the terminal and the clamping plate, without any need properly to wrap it around the screw head.

Flex ends need twisting and folding over before use, and should not go in the same hole as cable, or the flex connection can be weak and electrically inadequate. Lone cables going into a connector terminal are bent double to ensure good grip. The wire may be wrapped directly under the head of a screw, may be held by a metal plate forced against the wire by a screw, or may be held by what is, in effect, a set screw in the side of a metal tube. The wire may be directly stripped of insulation and inserted under the head of a screw or into the terminal. Otherwise, it may be either inserted first into a ferrule, which is then inserted into the terminal, or else attached to a connecting lug, which is then fixed under the screw head. MICC It was the only truly fire surviavble cable available just after the London Underground Kings Cross Fire. Sometimes, you want to connect several different circuits, and in such a case, you may opt to go for in-line connectors, such as the one shown in Figure 1.Soldering isn't a popular option for fixed wiring because of these issues, and because soldering takes some equipment and skill. There's also no readily available junction box designed for soldering. Its a good enough option if you've got the skill to do the job properly, but if not, other joint types would be better. Depending on the voltage and the current, there are standards that govern these connections. These standards are there for a reason, and you ignore them at your peril — sometimes in unexpected ways. For example, a friend had pot lights installed by some contractor at the lowest price. An insurance claim for an unrelated fire was rejected by the insurance company because the pot light installation was not to code. Bearing all of this in mind… In-line connectors This is simply a metal tube (sometimes insulated) in which you place the stripped end of one wire in one end of the tube, crimp it, and repeat for the other wire on the other side. Bullet connectors Crimping makes a connection reliable enough to be permanently buried. A good crimping tool is needed, cheap non-ratchet pliers don't make an acceptable joint. See crimp. Screw terminals, as individual connectors to a board at left, as a barrier strip with setscrews at top, and as a barrier strip with attached spade and loop lugs at bottom.