Are 16 mm meter tails good for 99A?

[Harry Worth]

Sorry folks if this topic is done to death. I've just been working with a spark who's put 16mm tails on a 100A fuse. I queried this and he responded with 'I'll show you in the regs - It's OK'. I've since tried to find the relevant table. Looking at table 4D1A - it gives 87A current carrying capacity for single core 70 degree thermoplastic clipped direct. Is this the correct table? The table doesn't show values for cables spaced or in free air. The tails in this instance are separated, short and not directly clipped to wall at some points. My question - does this mean the actual capacity can be taken as higher than 87A as the conditions are better than those in this table? If i take the 25mm table the capacity increases from 114A (ref method C) to 130A for spaced by 1 diameter. If I apply this factor to 16mm cable it suggests the cable is good for 99A (appreciate the calc's a bit rough and ready - I've probably ignored a square law). The house doesn't have an electric shower etc so current peaks are probably well within the 87A in any event.

 

[Johnuk]

as above

 

[DurhamSparky]

As per above posts !!! 25mm tails if the fuse was 100!!!

 

[mickys86]

I have a question (puts hand in the air)

What's an instantaneous shower?

 

[jaresquire]

You might get one with that question!

 

[brav]

electric shower

 

[DNG]

Tel can I ask. Would you always crimp the ferrule or as I have seen on web, could you leave the ferrule loose on cable end and allow terminal connection to compress the ferrule onto cable strands, ( sounds a bit iffy)

 

[trev]

Always crimp. The terminal could just deform the ferrule and not get a proper hold of the cable.
Just my twopennorth

 

[Guitarist]

Tel can I ask. Would you always crimp the ferrule or as I have seen on web, could you leave the ferrule loose on cable end and allow terminal connection to compress the ferrule onto cable strands, ( sounds a bit iffy)

Always crimp properly. As said, the strands may not be held properly if you only use the screw to "compress" the ferrule.

 

[Geordie Spark]

What size are the cables from the main fuse to the feed side of the meter? Are they 16mm? If so changing the load side tails only upgrades part of the installation,albeit the feed tails are the DNOs baby.
I worked for a DNO for a long time,and after fitting 16mm tails off an 100a main fuse since time began,one day it dawned on someone 16mm was rated about 97a so we then started fusing down to 80a.
I would fit 25mm as someone else has said, but I wouldn't lose a great deal of sleep over this either way.
Just a thought-have you actually checked the size on the fuse itself? It may say 100a on the carrier but it may be an 80a inside?

That would mean cutting the seal which we aren't allowed to do. :tongue3:

 

[telectrix]

Tel can I ask. Would you always crimp the ferrule or as I have seen on web, could you leave the ferrule loose on cable end and allow terminal connection to compress the ferrule onto cable strands, ( sounds a bit iffy)

sorry, mate. just seen the Q. beaten to it . always crimp with correct size crimp tool.