Heyes & Co. 'Lacent'

Bulkhead acquired in October 2024.

This bulkhead was acquired after I partook in the 'Hidden London' tour of the Second World War shelter at Clapham South, where a number of these bulkheads are installed on the ceilings of the shelter structure (and were during wartime, going on archival photographs of the complex that happen to feature them). Deciding while I was there that I liked their design, I managed to track one down. The 'Lacent' bulkhead was produced by Wigan firm Heyes & Co from the 1930s into the 1950s, as far as I can ascertain, with the examples at Clapham South being likely to date from the early 1940s (the shelter opened in 1942), assuming that they are all original to the site.

The bulkhead comprises a cast iron base and bowl support ring, with the prismatic bowl itself being glass. 'Lacent' features at either end of the support ring casting, with 'Made in England' positioned alongside the hinge. A single square-headed brass bolt located on the other side of the bulkhead secures the support ring to the casting, with a rubber gasket around the bowl making for a weatherproof interior under normal circumstances. Owing to the age of the bulkhead, the gasket has perished, but remains intact.

The refractors are arranged in a fan-like formation at either end of the bowl.

Although the base section is fairly deep on this example, others were deeper still, and employed two securing bolts.

Only a single cable entry features in this version - this measures ³/₄" in (19·05 mm) in diameter. Other versions allowed for multiple entries.

The locking bolt head measures ⁷/₃₂" across flats. Fortunately, this is virtually identical to 5·5 mm, allowing a modern-day brass radiator key to fit into the aperture.

Opening the bowl reveals the bulkhead's simple construction - a GEC brass bayonet lampholder attaches directly into the entry thread, with the idea being that the live and neutral conductors would terminate into it without any additional wiring (for this reason, I suspect that this could be an earlier version of the Lacent bulkhead, as other versions saw the lampholder separated from the conduit entry). There is no provision for an earth connection as this was not a requirement of lighting units when this fitting was made. Additionally, as the bulkhead would be likely to be used on a metallic conduit system, the earth path would be provided through the structure of the conduit itself, with a connection made back at the distribution board. Again, modern wiring requirements would dictate the installation of a dedicated earth conductor within the conduit. A shaped baffle plate painted in white enamel, and positioned behind where the lamp would be situated, serves as an internal reflector. The flaking white paint on the inside of the fitting body suggests that this too would have been given reflective properties.

Once the support ring is opened, the bowl is free to slide out - there is nothing to anchor it in position.

I purchased an adaptor to allow 20 mm conduit to fit into the narrower imperial entry - as can be seen, the thread required heavy cleaning, using the adaptor and a pair of mole grips, before a good connection could be made.

How the adaptor looks when fitted into the bulkhead.

The British Registered Name 510889 and Design 752721, and Australian Registered Design 9368, are cast into the rear of the base section.

A basic clean-up involving the use of an abrasive soap pad followed. This removed the majority of the flaking paint from inside the fitting.

The glassware was cleaned using warm soapy water.

The enamelled reflector also cleaned up well.

The reverse side is black but shows some white spray residue.

The lampholder was taken to pieces, and each one of these cleaned individually.

The GEC logo is stamped on the brass front section.

The part code SW520A is included on the porcelain inner section.

Once dried, the bulkhead was attached to the ceiling, with a 20 mm steel conduit end box added to accommodate the supply cable. As the end box features its own internal earth terminal, the connection was made there, rather than trying to accommodate one within the bulkhead. An OSRAM 4 Watt LED GLS lamp (with an equivalent output to a conventional tungsten 40 Watt lamp) was fitted.

The pearl finish to the lamp mimics the appearance of a regular tungsten lamp well.

With the bowl in place, the refractors moulded into the glass diffused the output considerably.

The underside appeared as one long illuminated section, thanks to the baffle plate.

Coughtrie PW.15 (Older version) |