Dear Sir

When we use different PVC master batches on wires with PVC Insulation, which colour will be the best for not decreasing the Insulation Resistance of the PVC Insulation.

Shall appreciate if the order of colours in terms affecting the Megger from bad to worst is given.

Hello again Reuben,

We never bothered to measure the insulation resistance of various PVC color masterbatch compounds. My experience was however that orange was typically a problem with insulated wire. We used our Munsell Book of Color Charts (Electrical Power Industry Color Standard) to reduce the amount of masterbatch used while still holding an acceptable shade of color. www.munsellstore.com/default.aspx?act=pr...sell+Color+Standards Gravimetric mixers are of course the very best way of accurately controlling the amount of color masterbatch used.

You must also have -40 C dried PVC compound and masterbatch. Absorbed moisture is definitely a common problem in your country and at your tropical location. Please see our previous message to you on this subject. www.wirenet.org/forum/viewmessages.cfm?Forum=8&Topic=945

As far as the insulation resistance of the various colors of masterbatch is concerned, we suggest you perform this experiment yourself with the properly dried, mixed and extruded insulation so that you develop a proper process standard. This will permanently resolve your problem unless of course you change color masterbatch suppliers.

Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212