You can replace the contact blocks with the standard ZBE101 (1NO) or ZBE102 (1NC) contact blocks with no issues.
If you wish to add contact blocks onto these items, you can again use the ZBE101 & ZBE102 contact blocks, but you must then get the item re-certified as ATEX compliant because the item will have been modified from its original ATEX certified state.
If you wish to add contact blocks onto these items, you can again use the ZBE101 & ZBE102 contact blocks, but you must then get the item re-certified as ATEX compliant because the item will have been modified from its original ATEX certified state.