electrical mysteries?

[Blue Duck]

pulled out a 7kw hob today(2x2kw 2x1.5kw),  It was connected to the outlet plate by means of a 1.5mm twin and earth cable that was totally unscathed!

I'm sure I've heard similar stories in the past.

Diversity... I wonderful thing.

 

[Tony S]

The only way to prove anything is a recording clamp meter during the christmas period. (Make sure you’re invited to dinner in your “official power monitor” role).

As you say, diversity is wonderful a get out of jail free card.

 

[Blue Duck]

It was probably 10 - 15 years old, I'm amazed that in that time it was never used near its peak!

 

[Evans Electric]

You do come across these things...you'd think that'll never work  but it does. 

One of the things that is difficult to calculate is the time characteristics ,  that flex is carrying its limit of say , 16A  but the hobs keep on switching on & off with stats ,plus they're not on for long , probably wouldn't have lasted in a commercial situation.

I was looking for an oddball MCB a while back to power a 10.5 KW shower  I think it was customer didn't want to change the board.  We had it working on a 30A  MCB  , RCD  upstream .   No one on here had anything bigger ,   but as Sidey pointed out , the shower will be on for about 10 mins max.  No long enough for the thermals in the MCB to  react , then its switched off . 

Two years , I've heard no more . Still working on the 32A.

 

[ProDave]

Well todays "electrical mystery" for me was a faulty light switch. 

No that's not the mystery, the colour coding was.

Wired in conduit singles, red for L feed in and feed out. Okay with that.

Two whites for the strappers out for 2 way switching of the landing light.

GREEN for the switched live out for the hall light.

I'm at a loss to know what eddition of the regs ever had those colours.

Conduit as CPC

 

[Evans Electric]

You think you've seen it all then , as you say, take a switch off & find white strappers and a green S/wire . 

 

[ProDave]

I've seen white as switched L before and thought jeez this is old (white used to be a phase colour, red/white/blue) but never green used as a phase colour.

I guess it's what was spare and nobody else looked.

 

[Davethsparky]

Well todays "electrical mystery" for me was a faulty light switch. 

No that's not the mystery, the colour coding was.

Wired in conduit singles, red for L feed in and feed out. Okay with that.

Two whites for the strappers out for 2 way switching of the landing light.

GREEN for the switched live out for the hall light.

I'm at a loss to know what eddition of the regs ever had those colours.

Conduit as CPC

9th edition had green as one of the phases of a three phase supply. 

Also part of WPDs power distribution area has an old network where brown green red were used for L1 L2 L3, its detailed in one of their technical documents if you search for it online.

 

[Evans Electric]

It sums up Britain doesn't it ?   All those different phase colours over the years .....FFS  just pick the colours in the first place and stick to them  .

 

[kerching]

It sums up Britain doesn't it ?   All those different phase colours over the years .....FFS  just pick the colours in the first place and stick to them  .

Or just use 

0........neutral

1,2&3 phases

seemed to work ok for lead cables

 

[ProDave]

9th edition in forrce from 1927 to 1934, which pre dates this 1950's house. So someone was working to old regs then.

 

[steptoe]

No change there then,

:|

 

[Davethsparky]

Or just use 

0........neutral

1,2&3 phases

seemed to work ok for lead cables

It was a lead cable system which had the brown, green, red colour coding 

see page 14 here https://www.westernpower.co.uk/getattachment/Connections/Competition-in-Connections/Engineering-Recommendation-Documents/G81-Appendix-doc.pdf.aspx

 

[phil d]

Many years ago when I was an apprentice,we fitted a really complicated heating system in my parents house and money was tight,I decided to try and get the electrical stuff from work,the idea was sound but the only cable I could get was green singles.The whole thing was wired in green singles,the earths were green and yellow mind,I often thought years later when we'd moved about the fun someone else would have had if they ever tried to fault find on it.Still typical electricians stuff back in the day,same with painters,you could always tell a painters house as the decor was usually in a poor state,doing it for a living usually meant you didn't want to be doing it when you got home.

 

[Tony S]

Similar to Phil but this time at work. A disboard isolator was having a quiet smoke as I walked past so I killed the feeder to it and opened the isolator up. I’ve caused a plant shutdown and I wasn’t popular. The isolator was toast as were the 70mm² singles to the boards busbars.

Something was needed PDQ. A rummage around stores didn’t come up with anything so time for a bit of creative thinking. I could have striped some 70mm² 3c SWA if it wasn’t tucked away at the back of the stores. I did find a drum of 50mm² G/Y singles, that’ll do. Connected in parallel between the isolator incoming and the busbars it solved the problem.

It took me about 2 years to get around to putting things right. Why rush? it’s working.

As an apprentice installing RWB cable was quite normal, it was in stores so we used it.

 

[Evans Electric]

Similar to Phil but this time at work. A disboard isolator was having a quiet smoke as I walked past so I killed the feeder to it and opened the isolator up. I’ve caused a plant shutdown and I wasn’t popular. The isolator was toast as were the 70mm² singles to the boards busbars.

Something was needed PDQ. A rummage around stores didn’t come up with anything so time for a bit of creative thinking. I could have striped some 70mm² 3c SWA if it wasn’t tucked away at the back of the stores. I did find a drum of 50mm² G/Y singles, that’ll do. Connected in parallel between the isolator incoming and the busbars it solved the problem.

It took me about 2 years to get around to putting things right. Why rush? it’s working.

As an apprentice installing RWB cable was quite normal, it was in stores so we used it.

OMG!! Not even I have installed RWB , seen it but not installed. 

Obviously Tony is a Blackley tape....3/4" conduit...metal fishtape, VIR  & tallow man  !   :Salute

 

[Tony S]

I have used 19/1.78 VIR but it was a temporary job, we were moving a board and again it was lurking about in stores and so we used it.

Altering a switchroom there was no way was I ripping miles of VIR out for the sake of replacing it. If it tested OK I used it.

We had some 45 year old VIR SWA tested at BASEC, “good for another 45 years”. A damn good job as there was miles of it in the crushing plant. It was cool and dry, ideal conditions.