What do the special symbols mean?
The 50 encircled with the two semicircular arrows is the China RoHS symbol for products with a 50 year life cycle. China RoHS has no exemptions, so the 3% lead (Pb) in brass components must be accounted for in this manner in WECO products. The e3 symbol stands for pure tin (Sn) plating as per the JEDEC standard no. 97. This is where lead free (Pb free) applies to the solderable coating that would be in contact with the solder wave, solder paste or solder iron during the assembly process. In a few optional products the solderable coating is e4; this stands for precious metals either gold (Au) or silver (Ag).
The RoHS is for the EU Regulation on the Restriction of Hazardous Substances in Electrical and Electronic Equipment, and compliance to the RoHS directive 2002/95/EC. The WEEE is for the European Union (EU) Regulation on Waste Electrical and Electronic Equipment, and compliance to WEEE directive 2002/96/EC.
Explain the difference between yellow chromated, passivated (clear chromated) and blue passivated screw plating.
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.
Can terminal blocks be grouped together?
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.
What is considered consecutive numbering for the WECO product ordering procedure? And special markings?
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.