Question on Reference Method A

[Licklieder]

Just wanted to check my understanding.

Am I right that running single phase cabling (single core, sheathed) in conduit embedded in a wall (recessed ~ 40mm) falls under reference method A ? Which from table 4D1A would then make the maximum allowable current for 1.5mm sq. cable 14.5A ?

I've got some 1.5 mm sq. radial lines running from my CU that feed electric heating in my flat and I wanted to check that I've got the right MCB installed

For the purposes of calculations, is the harmonised 230V used or 240V ?

 

[JohnW2]

Am I right that running single phase cabling (single core, sheathed) in conduit embedded in a wall (recessed ~ 40mm) falls under reference method A ?

I guess that depends upon what you mean by 'embedded' and what sort of wall we're talking about. As I understand it, it would only be Method A if it were in a wall full of insulation. In conduit in a masonry wall, it would be Method B, wouldn't it?

Kind Regards, John

 

[ban-all-sheds]

As I understand it, it would only be Method A if it were in a wall full of insulation. In conduit in a masonry wall, it would be Method B, wouldn't it?

For the purposes of calculations, is the harmonised 230V used or 240V ?

230V.

You may get a chap called winston coming along to tell you to use 240V. Ignore him - he is wrong.

 

[Licklieder]

Am I right that running single phase cabling (single core, sheathed) in conduit embedded in a wall (recessed ~ 40mm) falls under reference method A ?

I guess that depends upon what you mean by 'embedded' and what sort of wall we're talking about. As I understand it, it would only be Method A if it were in a wall full of insulation. In conduit in a masonry wall, it would be Method B, wouldn't it?

The conduit is in brick wall (or blockwork).

Ah. got it now yes, you are right. on going back to have another look at table 4A2, it looks like number 59 applies - Non-sheathed cables or single-core cables in conduit in masonry having a thermal resistivity not greater than 2 K.m/W o . should have kept turning the page. (only problem with online access - give me a book any time)

Good. A 16A MCB is sufficient then as table 4D1 gives a max rating of 17.5A.

 

[Licklieder]

As I understand it, it would only be Method A if it were in a wall full of insulation. In conduit in a masonry wall, it would be Method B, wouldn't it?

For the purposes of calculations, is the harmonised 230V used or 240V ?

230V.

Thanks

 

[JohnW2]

As I understand it, it would only be Method A if it were in a wall full of insulation. In conduit in a masonry wall, it would be Method B, wouldn't it?

The conduit is in brick wall (or blockwork).

That sounds like masonry!

Ah. got it now yes, you are right. on going back to have another look at table 4A2, it looks like number 59 applies - Non-sheathed cables or single-core cables in conduit in masonry having a thermal resistivity not greater than 2 K.m/W o . should have kept turning the page.

Yep, I reckon that's the one.

Kind Regards, John