Dear Panuwat
Please find attached Service report as per provided by Matco Thailand in the joint investigation.
According to the report, when it rain falls, it could cause rain to hit the junction box and water ingress through the transit plug at the junction box.
These transit plugs are not part of the Bill of Material in the schematic drawing and are just temporary plug to prevent any dust / dirt entry during transportation transit prior to the installation of cable gland by the end customer.
Hence these transit plugs are not water proof and are yellow / black caps are those left over / unused caps by other control equipment recycled to use for this transit purpose. This dust protection cap had been put installed for the past few batches without any issue.
In view of this situation, there is a need at your site to protect this cap area before your installation of cable gland commences.
From the review on the root cause, this ingress of water and causing rusty stains inside the junction box through the plastic transit plugs due to inadequate protection at the installation site shall not be under warranty.
However, in view of the long term good business relationship, we shall check / seek approval with our management whether we can swap new replacement of junction boxes to you and getting the rusty stain units return to us for further rework.
Currently, we have ex=stock of 10 pcs which unable to fulfill your total qty of 61 pcs. Our procurement shall check the lead time for purchase and shall revert to you again.