WECO's steel screws are typically zinc plated for galvanic corrosion protection. This active galvanic action protects the steel from rust even when the coating is scratched or porous. The lifetime of this galvanic protection is extended by passivation the exterior surface. This passivation is either yellow chromate passivation, clear chromate passivation or blue passivation. The yellow chromate contains Cr VI (soluble hexavalent chromium) a non-RoHS material and it has been phased out of use. The clear chromate passivation & the blue passivation are RoHS compliant and do not contain CR VI. They contain Cr III (insoluble trivalent chromium). The clear passivated has a reputation of being better for use as a test point under certain low voltage conditions & probe types.

Yes, terminal blocks can be grouped together while maintaining center to center spacing. Dovetail blocks are blocks that clip together with a tab and slot arrangement resembling a dovetail and have thinner outside walls, half the normal width, to maintain center to center spacing when they are clipped together.

Consecutive numbering is only when numbering begins at 1 with an increment of 1, (ex: 1, 2, 3, 4, etc.) and is oriented according to the sketch on the product web page. Any other numbering sequence, although possibly consecutive, is called special markings.

The only block supplied by WECO which is approved for environments of up to 500°C is the ceramic block, 560-K4DF-V2A.

Yes, by using jumper combs.

The RAST 5 standard is a coding sequence in Europe used by manufacturers of major appliances and consumer products such as whitewear (fridge, oven, etc.). This specific standard prevents mismatching of the plug and header to avoid short circuits on the PCB. Our 130 product family follows this standard and could be used for these specific applications within Europe.

As per WECO quality control procedures, insertion force and contact resistance after 100 plug/de-plug cycles has been verified and guaranteed.

When WECO speaks of continuous temperature limits, it refers to the material and not the environment. The temperature of a terminal block is a combination of heat generated by the electrical current flowing through it and heat exchanged with its environment. The heat exchange (inwards and outwards) with the environment is a combination of conduction, convection & radiation. The environment is the atmosphere, the enclosure, the wires, the mounting surface, other components and so on. We can see that the temperature of the environment is complex and cannot easily be reduced into the temperature of the surrounding air. We are concerned with hot spots in the connector's components (internal and external) and the material's ability to withstand this safely. Continuous temperatures always refer to the temperature of the connector materials. In the case that an RTI temperature is given, this means that the dielectric polymeric resin material was tested to UL 746B Polymeric Materials Long Term Property Evaluations and its Relative Thermal Index (RTI). This test last 5000 hours and the mechanical & electrical properties must not deteriorate more than 50%. Both UL 1059 Terminal Block Standard & CSA 22.2 no. 158 Terminal Block Standard refer to RTI. UL 1059 & CSA 22.2 no. 158 apply to ambient temperatures of 40 C (104 F) or less, the tests were done at 15 to 35 C (59 to 95 F). Ambient temperatures above 40 C (104 F), in principle and in practice, would require material review, special marking, extra testing and derating.

The approximate time for testing and reporting at the WECO lab is 2 to 4 weeks. Once it is completed it is approximately 6 to 8 weeks after submittal to UL and CSA.

The UV stability of plastics is the level of degradation of mechanical performance after exposure to sunlight. Acceptable levels of degradation are specified in standards such as: UL 746C, ISO 4582, BS EN 50021. Polyamides, which are used for WECO connectors do not have UV stabilizers and they are not intended for outdoor use.

WECO gives maximum torques for the wire tightening screws but does not give torques for mounting screws. The reason is that mounting screw torque will be very affected by the type of screw used and the substrate in which it is screwed. For example a wood screw into wood, plastic or sheet metal; predrilled or not, a machine screw & nut, will all have different torques. The important thing is not to deform, penetrate or break the connector dielectric moulding material because this could cause short circuits and other failures. As such the correct screw insertion criteria are correct final height of the screw head against the moulding and proper penetration into the mounting surface so as to be solid without damaging anything. The drawings on the website will help in determining this. This also requires that screw heads (and washers if used) be correctly sized. Too large can cause penetration into sidewalls and too small can cause excessive stress on the mounting hole.
WECO sometimes recommends a mounting screw type, but never torque.

UL and CSA recognized or listed terminal blocks have rated torques. Traditionally UL expresses torque in pound-force-inch (lbfin) and CSA expresses torque in Newton-meter (Nm). For example 1 Nm = 8.85 lbfin and 1 lbfin = 0.113 Nm.

These torques are chosen from UL and CSA tables or by the manufacturer. All cases involve the screws being tightened to the rated torque and the product being subjected to mechanical and electrical tests. This rated torque must be taken as a rating. It must not be exceeded because this could break or deform the connector. It must not be taken as a minimum because this could crush some small soft wires and provoke circuit malfunctions.

Choosing the correct tightening torque for factory wiring or for field wiring involves the knowledge and application of the ratings, torque measuring instruments, torque limited screw drivers, correct screw driver bits, correctly sized screw drivers, and the human factors involved. Mechanically assisted screw drivers (electrical, pneumatic, hand held or fixed) are especially sensitive to misuse. Torque measuring instruments and torque limited screw drivers must be used properly. Improper use can give false readings and incorrect torques. They all have finite accuracies, precisions and resolutions. The human factors involve the installer's strength, ability and choice of tool. In some jurisdictions electrical technicians must have the experience, education and tools required. Over tightening or under tightening can provoke failures that are not immediately obvious and cause overheating, fire or circuit failure. Screw driver bits must be correctly sized for the screw heads. Screw driver bit types such as Pozidrive, Phillips, Robertson and flat blade all perform differently. Screw heads such as Pozidrive, Phillips, Robertson and slot have differences and similarities of performance depending of what screw bit is used.

The pozidriv screw was designed by the Phillips Screw Co & the American Screw Co. It is designed to stay in and not to cam out. Using a Pozidriv screw driver bit in a pozidriv screw will allow higher torques than using a Phillips bit. It will also allow a higher torque than a blade bit while staying centered in the screw. Do not over torque product beyond its UL ratings. It is not necessary and it may crush the wires or break the connector. Click here for more information.

The ratings are assigned by regulatory agencies according to standards based on National Electrical Code. The values of the voltage and current rating for WECO Terminal Blocks are for both AC and DC applications.

Please click here for complete information.

WECO has removed the K suffix from its product code numbers (item masters). This does not change the product. The K only started to appear several years ago when the keyed back versions were phased in. The K was to differentiate the old from the new stock. The phase-in is now complete and the K suffix has now been removed on 99% of the products. The product is now labeled as WECO states it is.

Tin is a soft metal that adheres well to copper.

Dipping a properly prepared clean stranded copper wire into molten tin will agglomerate all the strands. No strands will be loose to twist out of the wire entry. Loose strands could cause a short circuit or reduce the available current carrying capacity.

Tin has a low contact electrical resistance because it is soft. Tin is so soft that moderate contact forces tend to squeeze it so that the microscopic contact points spread into each other. The effective contact surface area is thus increased.

In the case of the high contact forces occurring in screw tightened connections tinned wires or bare wires would have the same contact resistance.

UL 1059 and CSA 22.2 no. 158 terminal block standards require that bare copper wires be used during testing.

Yes, WECO Electrical Connectors Inc. has this ISO statement.

Yes, they meet Restriction of Hazardous Substances in Electrical and Electronic Equipment (RoHS) Directive. WECO has this RoHS statement.

Yes, they meet the Registration Evaluation Authorization and restriction of Chemicals (REACH) regulation as it is defined now. WECO has this REACH statement.

Product change notice for 971-SLK as of 7 May 2010

WECO 971-SLK family of pin-strip type headers is being improved. A better, straighter, higher temperature resistance, reflow soldering process compatible and more user friendly product is being phased in. The overall dimensions will not change. This product is a drop in fit into your process and existing printed circuit boards. It is being phased in FIFO.
We intended to call this product 971-SLR, however, surveys of our customers have shown that the majority would prefer no change in product names or product codes. We are thus calling the product 971-SLK…# and 971-SLK…^.
This tactic is being used so that you, the distributor, CEM, OEM and onwards do not have to go through a change in your bills of materials and other documents that refer to WECO’s connector. The UL, CSA and all regulatory situations are all cognizant of this.
The 971-SLK…# & 971-SLK…^ bills of materials will be calling out for a symmetrically shaped moulding type MLD971SLRTHR with a pin of slightly different shape.
Should you wish to have a new product code, you will be a given a code starting with 971-SLR.

• The 971-SLK pin-strip with a 1.3 mm diameter pin plug-end and a 1 mm diameter pin PCB end willhave a ^ suffix. For example: 971-SLK/06 becomes 971-SLK/06^. 971-SLK/02-G30 becomes 971-SLK/02-G30^. 971-SLK/04-006 becomes 971-SLK/04-006^.
• The 971-SLK pin-strip with a 1.1 mm diameter pin plug-end and a 1 mm diameter pin PCB end will have a#suffix. For example: 971-SLK/06-001 becomes SLK/06-001#. 971-SLK/04-001 becomes 971-SLK/04-001#. 971-SLK/04-002 becomes 971-SLK/04-002#.

The major difference between a genuine surface mount terminal block and through-hole reflow terminal block is that the surface mount does not require any type of holes in the printed circuit board in order to make the solder assembly.

The major similarity between the two is that both are assembled to the surface of the PCB by using re-flow technology. Re-flow technology requires an oven that heats (by convection or radiation) up to 260 - 270 degrees Celsius to melt the solder paste between the contact element and the PCB pad.

An example of a SMarTconn terminal block of THR type is 970-THR. An example of a SMarTconn terminal block of genuine SMT type is 140-A-126-SMD.

Using genuine SMT products increases the surface utilization of the PCB, since you can use both sides. It is appropriate for pick & place automated assembly and completely eliminates PCB damages that are inherent to THR products. Basically it is the higher reliability and the cost impact at PCB assembly level, that make the genuine SMT product line the option of the future.
The disadvantage of the genuine SMT product line is the weaker retention strength of the contact pins to the PCB pad, and the need to change the PCB layout when making the shift from THR to SMT.
Despite the assembly strength and reliability of THR connectors, during the first decade of the new century, the shift between THR and SMT will become more and more popular.

WECO components and products do not contain rare earth elements.

1. SCCR ratings have long existed in United States for certain components such as fuse holders.

The SCCR requirement was expanded with the release on the 2005 NEC, where marking of SCCR became required to:

HVAC equipment

Industrial Control panel

Industrial Machinery

Meter Disconnect Switches

Motor Controllers

Subsequently in 2006 this requirement has become a part of:

UL508A for Industrial Control Panels.

UL1059 for Terminal Blocks, supplement SA1, 2, 3, and 4, as optional

2. WECO Terminal Blocks type 302 (HDS), 323(HDS), 324(HDS), 326(HDS), 327(HDS), 327-FU(HDS)

are approved according to requirement of standard UL1059.

WECO Terminal Blocks type 302 (HDS), 323(HDS), 324(HDS), 326(HDS), 327(HDS), 327-FU (HDS)

are not evaluated for Short Circuit Current Rating yet.

WECO Terminal Blocks type 302 (HDS), 323(HDS), 324(HDS), 326(HDS), 327(HDS), 327-FU (HDS)

don’t have SCCR.

Customer may use WECO products and evaluate the final assembly (control panel, machinery, equipment) for SCCR.

3. Terminal Blocks type 302 (HDS), 323(HDS), 324(HDS), 326(HDS), 327(HDS), 327-FU(HDS)

are approved by regulatory agencies in North America and Europe

            3.1.      UL safety standards UL1059 and UL486E

            3.2.      CSA safety standard C22.2 No.158

            3.3.      European safety standards

DIN EN 60998-1(VDE 0613-1), DIN EN 60998-2-1(VDE 0613-2-1) EN 60998-2-1