Loose Neutral in Consumer Unit

[aesmith]

Hi,

We've been trying to to track down some alleged RF interference at home, and one of the suggestions was that it could be a poor connection somewhere in our electrics. I decided to switch off at the meter cabinet, where we have an isolator on our side of the meter which switches off everything in the house and the outbuildings. The idea was to have a thorough check in the outbuildings, particularly where I had installed the final circuits.

However while the power was off, I took the front off the house CU which had been installed during the full house rewire in 2011. Almost immediately I spotted a loose neutral, not just loose but backed out almost all the way and the wire just "sitting" in the hole. By good fortune that was the immersion heater circuit which we have actually never used. Of course it only took a moment to tighten it down. However I don't really know what to think. That was a professional job and I had no prior concerns about the job or the workmanship. It was just one screw, maybe easy to miss, but couldn't that be dangerous if the circuit had been used?

Would be interested in comments.

Tony S

 

[Marvo]

It's not uncommon for terminations to become loose over time, even correctly made terminations, they should really be checked for tightness periodically. In the good old days most of the neutral bars used to have dual screws for each termination but not so much nowadays which also doesn't help. It's not necessarily a reflection on the standard of the rest of the installation but I'd suggest you check all the CU terminations whilst you're at it, just isolate it first so power is off.

 

[aesmith]

Thanks. I did check all the others and nothing else was remotely loose, only that one screw that was standing out a good 2 or 3mm compared to the others. I wouldn't have expected it to back off that far all on its own, but there you go. What sort of interval would you check things like that? It's easy enough to check for someone who's happy to go into the consumer unit, although I'm not sure I'd be so confident if we didn't have that outside isolator to shut everything off.

 

[amlu]

Thanks. I did check all the others and nothing else was remotely loose, only that one screw that was standing out a good 2 or 3mm compared to the others. I wouldn't have expected it to back off that far all on its own, but there you go. What sort of interval would you check things like that? It's easy enough to check for someone who's happy to go into the consumer unit, although I'm not sure I'd be so confident if we didn't have that outside isolator to shut everything off.

if the screws were made properly tight by an experienced electrician they are supposed to stay tight.
otherwise it should be checked every couple of years, on the paperwork given to you by the electrician it should say when its the next inspection due.
what kind of RF problems you have?

 

[aesmith]

Cheers. The certificate and sticker recommend next inspection in December 2021, I think that's normal isn't it, 10 years?

RF problems - this is interference on broadband, the so-called REIN. I'm not convinced it's the issue, but the OR guy was picking up some noise with a 50Hz element so I wanted to check everything I could. They test for this with an AM radio on 612kHz as a rough and ready detector, so I was doing the same when I switched things back on. I didn't pick up anything except from appliances or fluorescent lights and in these cases the signal drops right off when you move a few feet away so clearly coming from that source and not radiating from the wiring.

 

[amlu]

Cheers. The certificate and sticker recommend next inspection in December 2021, I think that's normal isn't it, 10 years?
RF problems - this is interference on broadband, the so-called REIN. I'm not convinced it's the issue, but the OR guy was picking up some noise with a 50Hz element so I wanted to check everything I could. They test for this with an AM radio on 612kHz as a rough and ready detector, so I was doing the same when I switched things back on. I didn't pick up anything except from appliances or fluorescent lights and in these cases the signal drops right off when you move a few feet away so clearly coming from that source and not radiating from the wiring.

Properly made installation should be fine after 10 years if no one was messing around with it... Little bit too long for me, but may be fine for the guy installing it.
RF - 50Hz is the grid frequency, and the interference will be most likely generated by something you plug in, not the actual wiring itself.
Those little phone chargers, power supplies, transformers etc - with cheap electronics and no quality control anything could happen.
If you have a way of testing it - start a measurement and try unplugging whatever is connected one by one, turn off the lights too, see if it helps.
Make sure your modem is connected to the master socket and all phone extensions are unplugged.

Or it maybe just the phone line itself - they are really old, some not it the best condition for ADSL usage...
Swap for for virgin cable broadband if they operate in your area (worked wonders for me)