Disconnecting old Pyro supplied lighting

Hi, I've searched and searched for information on this topic but can't seem to find any answers on it. I am currently renovating two rooms in my house and I'm looking to include dimmer switches in both however the existing lighting circuits (or 6A radial circuits) of which there are 2 are both run in Pyro/MICC have back boxes that are too small for a dimmer. My plan is to connect to one of these circuits via a new 1.5mm connection that was hooked up for our kitchen about 3 years back as both rooms are already on this same circuit through the pyro. My challenge is that I will want to disconnect the old Pyro runs for each of these, I have found the junction box and located the correct connections however as the the junction box has other connections that will still be in use how can I seal the holes left by the disconnected runs? 

Are the holes threaded?

kerching said:

Are the holes threaded?

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Hi, thanks for the response. Just had a quick look at light switch and it looks like they are threaded the junction box had the same pots/connectors. Photos

Well  tHats a first!  Have NEVER seen that type of Pyro gland before, ever!

looking at the back box and the MK conversion brackets I would say it dates from the 50s and is most likely Imperial 3/4" thread.  Which is a Barrymore.  You can get a 3/4" to 20mm converter and then fit a 20mm blanking plug OR can you not just change the box if you are scrapping the pyros?

Ah....my bad. You want to KEEP the junction box?

source the converters and blanks then.  Unless you can get 3-4" blanks but they are rarer than a straight 70s TV presenter

kerching said:

Well  tHats a first!  Have NEVER seen that type of Pyro gland before, ever!

looking at the back box and the MK conversion brackets I would say it dates from the 50s and is most likely Imperial 3/4" thread.  Which is a Barrymore.  You can get a 3/4" to 20mm converter and then fit a 20mm blanking plug OR can you not just change the box if you are scrapping the pyros?

Ah....my bad. You want to KEEP the junction box?

source the converters and blanks then.  Unless you can get 3-4" blanks but they are rarer than a straight 70s TV presenter

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Okay thanks, yeah the house is an Atholl Steel 1945 so I assumed they came with it along with the 4mm socket wiring. I'll look into the converter seems like the best way to go. 

Perhaps a bit rough and ready but why not just cut off the pyro outside the box and its tails inside, and leave the whole gland assembly in place?

Geoff1946 said:

Perhaps a bit rough and ready but why not just cut off the pyro outside the box and its tails inside, and leave the whole gland assembly in place?

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Yeah I did consider that option and I suppose that it would still make it safe and keep the junction box sealed from moisture, might be the way to go. I had sourced the parts as Kerching had suggested but have not ordered them yet as I wanted to check the gland size. 

kerching said:

Well  tHats a first!  Have NEVER seen that type of Pyro gland before, ever!

Click to expand...

Neither have I  ...looks like a grub screw in the gland .    As we often say on here ,  theres always something you've not seen before  even after all those years .