Checking surplus cable before you buy it

1. Read the sheath

BASEC lists what to look for on a cable's outer sheath (cable markings and identification):

• the manufacturer's name or logo and a traceability mark;
• the standard the cable is made to;
• the voltage rating, for example 600/1000V;
• the BASEC mark, and the HAR mark on harmonised cable.

BASEC is direct about its own mark: "If the word 'BASEC' is not visible on the cable it is not BASEC approved." The mark should also appear on the drum and packaging. Some cable carries coloured threads that indicate the year of manufacture.

Check the standard against the type. Single-core 6491X, for example, is now made to BS EN 50525-2-31, the standard that replaced BS 6004 for that type; flat twin and earth (6242Y) is made to BS 6004. Armoured cable is commonly BS 5467, or BS 6724 for the low-smoke, zero-halogen version. The current datasheet for the exact product is the authority, not a list on a website.

2. Look up the approval

BASEC runs a free cable, certificate and company search. Approvals carry a certificate number and an expiry date. Two cautions from BASEC itself: test reports are not published online, and some licensees have asked not to be listed, so a cable that does not appear in the search is not proof of a fake (verifying approved cables). Ask the seller for the certificate number and check that.

3. CPR class and declaration of performance

Cable permanently installed in buildings is classed for reaction to fire, from Aca down to Fca, with additional classes for smoke, flaming droplets and acidity, for example Cca-s1b,d1,a1. The class and the declaration of performance (DoP) are normally on the drum label and the manufacturer's DoP rather than printed on the cable; BASEC notes the UKCA or CE marking belongs on the packaging label and the DoP, not the cable.

In Great Britain the CE mark continues to be accepted on construction products alongside UKCA (GOV.UK, construction products). Ask for the DoP, or its reference, with the drum. A specifier will want the class to match the job.

4. How much, and in what state

For a part-used drum, ask for the metre marks at both ends where they can be read, or the gross weight, the drum's empty weight and the datasheet's weight per kilometre. Datasheet weights are approximate, so treat a weight-based length as an estimate. Ask whether the ends have been kept sealed and how the drum has been stored: manufacturers advise sealed ends, drums kept upright on their rims and protection from rain and sunlight (Prysmian user guide).

5. Where it came from

Ask for the original supplier and invoice date. Provenance is what ties a drum to its approval, and it rules out old problem stock. The 2010 recall concerned cable marked "Atlas Kablo" with a 2010 date, and not all of it was recovered (ACI, 2017).

6. Check the business selling it

• Companies House search: is the company active, and does its registered address make sense for the seller?
• Check a UK VAT number: does the number on the invoice belong to the business you are paying? You need the number; the service does not search by name.

None of these checks makes a cable safe for a particular installation. That decision belongs to whoever designs and certifies the installation, working from the manufacturer's datasheet.