cable and hole size?

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I've just put a cu in my garage, which is attached to the main house. This is feeding Lights, sockets (5 doubles) and the garage door. I have run 10mm cable from the main CU to the garage, under the floorboards through the wall. Up the wall in conduit and into the second CU. Is this acceptable. The lighting cable (1.5) is run through the joists 13mm hole. Can I run more then one cable through the same hole or should I drill a second hole next to it (not closer than 3x dia of hole). I was going to put the garage door on a FSU with a 16A mcb. is this correct.
 
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Bignev, as you have stated that you used conduit would I be correct in assuming you have not used SWA but Twin and Earth cable to supply the Garage?

If my assumption is correct, then your installation is INCORRECT. You should use SWA for such an installation. T&E is not rated to operate in that environment. That is not to imply it is dangerous or anything of that nature, but it would be considered bad design and also a breach of the regs as the installation was not carried in accordance with the Supply Regulations Act etc...bit of a grey area in a domestic I know, but SWA should really be used to feed external supplies, with a RCD at either end.

Nothing wrong with using a FCU to supply the Garage door, might be an idea to drop the MCB to a 10A, depending on the rating of the motor, but this MCB should ideally be a D type not a B type.
 
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FWL_Engineer said:
Bignev, as you have stated that you used conduit would I be correct in assuming you have not used SWA but Twin and Earth cable to supply the Garage?

If my assumption is correct, then your installation is INCORRECT. You should use SWA for such an installation. T&E is not rated to operate in that environment. That is not to imply it is dangerous or anything of that nature, but it would be considered bad design and also a breach of the regs as the installation was not carried in accordance with the Supply Regulations Act etc...bit of a grey area in a domestic I know, but SWA should really be used to feed external supplies, with a RCD at either end.

Nothing wrong with using a FCU to supply the Garage door, might be an idea to drop the MCB to a 10A, depending on the rating of the motor, but this MCB should ideally be a D type not a B type.

Narf Narf Narf
Do you ever read posts properly. the above is NOT in the slightest bit relevant and is in fact absolute rubbish, rubbish rubbish. This man asked a simple question and without even reading the thing properly you went mad. Did you not know that the garage was connected to the house. I could understand if it did not clearly say, but it did so so so so clearly

I've just put a cu in my garage, which is attached to the main house.

you are such an eejit not to have seen this and it written in plain english.
SWA! What the hell are you on?? this gentleman was perfectly correct and away you go narfing narfing about SWA! I honestly think you should get glasses before you go and crash your vectra. You Fool.
 
Looks like Jim has made a new friend.... :confused:
 
Be fair.

To err is human. To really mess up....................
 
Point taken about the Garage door I'll check. Is the type D to avoid nuisance tripping? Yes the Garage is an integral part of the house. Is the 10mm T@E ok (large enough). Is it acceptable to run multiple wires through one hole in a joist (1.5 T@E).
 
bignev, you have clearly gone to great trouble to ensure that this installation is neat safe and well designed which is great to see.

Q1. There are complex formulas for working out the exact size cable required for certain loads. However as far as you are concerned, 10mmsq T&E is rated at 45A. This cable should therefore be protected with an 45A MCB at the house C.U. you may find it easier to get a 40A and this is ideal.

40A/45A is a more than adequate supply for a garage in my opinion.

Q2. MCB's are 'rated' in two ways:
A Their 'load rating' (10A,40A,45A etc.)
B Sensitivity to starting current (which is denoted by letters). generally you will find MCB's in B(most sensitive) C and D(least sensitive)

Type B are the standard type of MCB's for use in domestic installations.

In answer to your question yes the use of a type C (which i think would be adequate) or type D breaker for your garage door circuit is to prevent nuisance tripping. It would also be advisable to use a type C MCB in you house CU so as to prevent it tripping as well as the appropriate garage MCB should a fault occur in the garage.

So to sum up:
Garage CU: all B type, except door circuit, which should be C type.
House CU: C type (using a D type here (although not a major issue) might prevent the installation from meeting the required disconnection time.)

Is it acceptable to run multiple wires through one hole in a joist (1.5 T@E).

Yes, good judgement has to be used here. it would not be advisable to tightly 'bind' cables together in a hole, but provided there is plenty of space (13mm hole sounds fine) their is no problem.

I have purposely gone into detail with this, so as you fully understand not only how but why something is done so as you are able to use a second C type breaker in your garage for example if so required (say you have a large table saw!)

House CU: C type (using a D type here (although not a major issue) might prevent the installation from meeting the required disconnection time.)
perhaps someone can advise of uk regs on this
 
To err is human. To really mess up takes a "...................."

During a rewire, I drilled 1.5 inch holes in the centre of 6 inch bathroom floor joists (Which is Acceptable)
Then along came the "Plumber" who cut out 1.75 inch notches directly above my holes for the central heating pipes, :(
Thus reducing the effective thickness of the joists to less that 3 inches :(
This floor has now got to suppurt a 28 stone person in a cast iron bath full of water :evil:

I really look forward to your comments :eek:
 
suppose bracing the damaged section on either side is the only way to go.
Classic case of doing your job(plumbing) and forgetting about the real job (house)!
 
BR said:
suppose bracing the damaged section on either side is the only way to go.
Classic case of doing your job(plumbing) and forgetting about the real job (house)!

Excuse Me :confused: I Was doing the electrical work, The "Plumber" did his "Disaster" after I had finished :cool:
 
it was a general comment, not directed at you :) should have made it clearer.
 

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