What size cable... this time a funny.

[SUNRAY]

Middle of last week I helped faultfind the supply to a garage. Quite urgent as there is now an electric only car parked in there.

Turns out it's far too thin, looks like 1.0mm² [but could be 1.5mm²] on a 32A type1 MCB in a duct with obvious signs of overheating.

The boss was on the phone to the office about something unrelated to the job and asked the buyer to use the online calculator and order replacement cable. 36metres, 32A, buried. the calculator said 50mm². It turned up yesterday...

Lucky the boss laughed about it then said there is another job it can be used on.


Me thinks a decimal point in the wrong place or something.

 

[JohnW2]

Middle of last week I helped faultfind the supply to a garage. Quite urgent as there is now an electric only car parked in there. Turns out it's far too thin, looks like 1.0mm² [but could be 1.5mm²] on a 32A type1 MCB in a duct with obvious signs of overheating.

The EV obviously totally moves the goalposts, but I suspect that (with an appropriate OPD) 1.5mm² (or even 1mm², if it were 'allowed'!) would probably be theoretically adequate for the electricity requirement of many/most garages!

... the calculator said 50mm². It turned up yesterday... Lucky the boss laughed about it then said there is another job it can be used on. Me thinks a decimal point in the wrong place or something.

5mm² cable? Given the standard range of cable CSAs it's difficult to see how it can be a error like a moved decimal point. What do you think it should have been - someone who needs to go to Specsavers might conceivably have read or written 50mm² instead of 10mm² ?

Kind Regards, John

 

[ericmark]

I remember my boss ordering 50 mm² flex for concrete pumps, when it arrived the client Nuclear Electric said your not using flex, needs to be at least braid, prefer SWA, try hiding 50 meters of 50 mm² so no one asks questions of why not used.

He did not give up, he ordered braid and shrink sleeve to go over it, one guy tried to fit a 125 amp plug, no chance, often wondered what happened to it?

 

[SUNRAY]

The EV obviously totally moves the goalposts, but I suspect that (with an appropriate OPD) 1.5mm² (or even 1mm², if it were 'allowed'!) would probably be theoretically adequate for the electricity requirement of many/most garages!
5mm² cable? Given the standard range of cable CSAs it's difficult to see how it can be a error like a moved decimal point. What do you think it should have been - someone who needs to go to Specsavers might conceivably have read or written 50mm² instead of 10mm² ?

Kind Regards, John

This a 60's house and I'm also guessing and the expected garage load would have been fairly low, a 10A supply was very likely more than adequate then.

I'd just assumed the data was input incorrectly and hadn't given much thought to what was done wrong.
I've tried Cleveland on line calculator and it gives 6mm² @ 5% 10mm² @ 3% [I'd go for 10mm² if funds allowed] 360m gives 70mm² but 359m gives 50mm² so my guess is a different calculator at 360m gave 50mm²?

 

[SUNRAY]

I remember my boss ordering 50 mm² flex for concrete pumps, when it arrived the client Nuclear Electric said your not using flex, needs to be at least braid, prefer SWA, try hiding 50 meters of 50 mm² so no one asks questions of why not used.

He did not give up, he ordered braid and shrink sleeve to go over it, one guy tried to fit a 125 amp plug, no chance, often wondered what happened to it?

I've not tried but my initial thought is 50mm² will go in a 125A plug ok. In fact the same calculator give 50mm² for 70m or 35mm² for 60m or 10m

 

[muffking]

Did someone say the decimal point was in the wrong place

 

[delmel]

Just imagine the drill you would need lol

 

[ericmark]

It was the braid and shrink sleeve that made it hard, he did actually fit one plug to the cable, it was a long job, and cable was so stiff it was not really practical to plug in.

Radial arm drilling machine, we do have one where I work, clearly everything bolted down before you drill.