Chinese CH2 terminal block (CH1 CH3)

I purchased some CH2 terminal blocks on eBay. They were advertised as 250V AC, 10A, to suit 2.5mm^2 conductors.

Above is the seller’s pic of the terminal block.

Features:
– Fast wiring
– Prevents the wire from shorting out
– Free drilling screws, increase the speed of assembly
– Can completely replace electrical tape
– Cost savings
– Fast、efficient and safe
– Widely used in the wire connection,especially for LED Lighting Ceiling
– lamp dedicated wiring clip.

Specification
– Material: PP Flame Retardant Plastic
– Reed material: Manganese Steel Sheet
– Color: White
– Voltage: 220V
– Current: 10A
– Type: 2Pin Connector
– Style:Self-locking Cable Connector
– Temperature: -40 to 150 Degrees Celsius
– Wiring: Wiring Capacity From 0.5-2.5 Square Wire
– Size: CH-2:Approx. 20*17.5*13.5mm

Close inspection cause me concern for their performance, there is no current rating marked. The product is labelled KX-P2 and appears to be a product of Foshan Shunde Kaixiang Electrical Co Ltd, but the Chinese being great copyists, this may have come from another source.

They will not accommodate more than a single 0.75mm^2 conductor in each end, about 30% of the claimed 2.5mm^2… the Chinese lie.

The contact springs are weakly magnetic, so they may be some mid to low grade stainless steel, eg 304 (inconsistent with specification of manganese steel).

A first test was setup to pass 5A though the connectors using 1mm^2 copper conductors.

At 5A in just one terminal, the connectors get quite hot. The voltage drop between ends of the internal contact strip at 5A was 155mV, these are not going to be a high current terminal. An IR thermograph shows the exterior reaching 40° in just a couple of minutes. In fact at 2 minutes, the circuit disconnected due to plastic flow of the insulation. If the temperature spec was correct, the melting temperature would be above 140°, so the thing got hot… but yes, the Chinese lie, who knows that T really is?

Above is a close up of the left terminal used for the test. It can be seen that with 2min @ 5A, the plastic melted allowing the wire to melt the groove that can be seen, reducing the tension on the wire and it actually went open circuit saving it from further damage. Note that the plastic has fused around the actuator pegs for the left hand button, it is now frozen solid.

On a reduced test at 1A, the temperature rise was much less, they are just warm and probably acceptable. They are probably suited little more than 1A, 10% of their advertised rating, and 1% of the ohmic dissipation.

These are also available as 1way (CH1) and 3way (CH3) blocks.

Cheap Chinese junk! The purchase cost was refunded by eBay.

Update: 24/04/2020

Foshan Shunde Kaixiang Electrical Co Ltd did contact me after I browsed their page, and I asked them for the current rating for the terminals. They advised the price, but not the current rating. After some to and fro, they advised 2A for the Polypropylene with stainless steel contact strip (as above) and 15A for the Polyamide with copper contact strip.

At 2A, the stainless ones drop 0.54V, so 1.1W of dissipation (per terminal). The measured temperature increase of the stainless steel contact strip at 2A was 43°, rather high and suggests the 2A rating is pretty adventurous… very Chinese.