cables under suspended floor on dirt.

[1Justin]

1930's house with timber suspended ground floor over dry dirt. No depth for access. Existing ring final and radial circuits run under floor, and cables are thrown into the space, mostly resting on the dirt, maybe a clip here or there, but only usually for efffect where they perhaps get near an access hole and someone might have added one to make it look neater!

So if I am extending such a circuit(s), and need to add additional cable under the floor. - I own the whole circuit now.
A) I can't get the existing cables out of the dirt. I can't find what 17th would say about this.
B) I can't clip my new cables to joists because I have no access. Repeating the old method (throwing them in) feels wrong, although the cable would technically be mostly supported (by the dirt).

What to do? - And it will be inspected job for NICEIC.

Justin

 

[i=p/u]

run a new circuit and leave alone

 

[1Justin]

That's one way, but it shirks responsibility in a way I'm not entirely comfortable with. I can't just leave this example alone since an open ring needs repairing on one section, - so I'm in there anyhow.

Anyway, how would you support new circuit under the boards? (Let's try and keep it under there for the moment or we open a whole new set of work in this house)

Justin

 

[ash_s3]

can you suspend a steel catenery wire under the joists from either end of the room?

 

[i=p/u]

bound to be joist to clip too, dig muc/ catenary wire,, just stick it in conduit. hmmmm any pics?no, ok. i always have camera in car


with aid of diagram

 

[trev]

How much of a gap are we talking about between the dirt and the floor. I'm thinking a skinny apprentice would come in handy here.

 

[Engineer54]

Is this dirt floor damp or dry?? If it's bone dry, i can't really see what your problem is...

 

[1shortcircuit]

Supported is supported whether it be resting on plasterboard or on dirt. My concern would be continuing such support when coming from dirt to socket so would probably insert a timber into dirt and fasten to joist when coming up to socket. Got one like this myself coming up about 2 foot gap, clutter galore beneath (Health and Safety says) I am not going in and if I am not prepared to go in then neither will I ask anyone else to go in.

 

[i=p/u]

in china this week engineer54, ?? heard there was a load of pat testing out there..

 

[micknew]

Is this dirt floor damp or dry?? If it's bone dry, i can't really see what your problem is...

Totally agree.

 

[Engineer54]

in china this week engineer54, ?? heard there was a load of pat testing out there..

Only in your dreams i=p/u, ....Only in your dreams...lol!!

 

[1Justin]

Yes the dirt floor under is dusty bone dry. There isn't room for even a skinny apprentice to get in!
I like the idea of adding a timber to support if necessary.

Catenary wire - potentially could be done that way I guess, yes. Might one conventionally just use some braided galv steel cable and perhaps tie-wraps (which would work just fine I guess)?

But earthing the catenary? Regs say only if it's trunking or conduit, so I assume earthing a steel catenary isn't then necessary.

To avoid the problem entirely IMO, why not just use pre-streched polyester braid (or dyneema if we want absolutely no stretch). Would be safer and much easier to work with than steel cable anyway. Leave a little slack, strap on the cable ties every~250mm, (or use heat-shrink tube straps), pull it in, tie it off both ends.

- And why not? - Have I just fixed my problem?

Justin

 

[danzor]

Sounds like a 10 min job is going to be a 3 hour job

 

[Richard]

But earthing the catenary? Regs say only if it's trunking or conduit, so I assume earthing a steel catenary isn't then necessary.

Hi,

IMO a catenary wire would fall under the bracket of exposed conductive part, so I have always earthed them. But i'm happy to be corrected on that!

Rich

 

[1Justin]

OK, thats' undoubtedly true. Hence maybe easier to use a rope? - Why not?