Jump to content

DONT STAY LURKING AS A GUEST,

JOIN TEF AND BENEFIT FROM MEMBERSHIP:

CLICK HERE TO JOIN.

Pvc V Xple


SLIPSHOD & SLAPDASH

Recommended Posts

Is there a sure-fire  way of knowing if a SWA is PVC or XPLE if you can only access the 'tails' inside a DB ?

xple  normally has a 'waxier' feel but harder than pvc

Link to comment
Share on other sites

apart from chemical analysis, I can't think of anything.

Link to comment
Share on other sites

set fire to it? see what it smells like?

:C

Link to comment
Share on other sites

I have had some XLPE recently where the colouring was almost transparent and you could "sort of" see the twists through the ins. BUT it was a kosher make

Just saying

Link to comment
Share on other sites

You could measure over the insulation of the cores & OD of the incoming sheath, they are different between the PVC & the XLPE versions.

Unfortunately the sizes are in the BS which is stupidly expensive, though, if you can see the manufacturers name on the outer sheath then you could check their data.

Link to comment
Share on other sites

You could try putting a piece in an oven at just over 140 degrees C (along with known pieces of pvc and xple) and see whether it breaks down? AFAIK pvc should, xple shouldn't.

"The heat stability of raw PVC is very poor, so the addition of a heat stabilizer during the process is necessary in order to ensure the product's properties. PVC starts to decompose when the temperature reaches 140 °C, with melting temperature starting around 160 °C."

"Almost all cross-linkable polyethylene compounds (XLPE) for wire and cable applications are based on LDPE. XLPE-insulated cables have a rated maximum conductor temperature of 90 °C and an emergency rating up to 140 °C, depending on the standard used. They have a conductor short-circuit rating of 250 °C."

Link to comment
Share on other sites

AFAIA most of SWA is XPLE now days,,, however I always calc for PVC as I can't guarantee that the terminations will be rated for the higher temperature......

Link to comment
Share on other sites

You could measure over the insulation of the cores & OD of the incoming sheath, they are different between the PVC & the XLPE versions.

Unfortunately the sizes are in the BS which is stupidly expensive, though, if you can see the manufacturers name on the outer sheath then you could check their data.

 

 

Sometimes has a BS number on it

 

 

I have no access to the SWA except in the DB .

 

 

AFAIA most of SWA is XPLE now days,,, however I always calc for PVC as I can't guarantee that the terminations will be rated for the higher temperature......

 

 

My local independant always supplies PVC unless XPLE is specifically mentioned .

I have inspected a job (awful work) done only 5 months ago by a NICEIC contractor. One of the many things is a 6mm, 3c swa buried for about 18m with a 40A , B type breaker. If its XPLE its ok.

Link to comment
Share on other sites

Not the one with a nice shed is it?

Link to comment
Share on other sites

I have no access to the SWA except in the DB .

 

 

 

 

My local independant always supplies PVC unless XPLE is specifically mentioned .

I have inspected a job (awful work) done only 5 months ago by a NICEIC contractor. One of the many things is a 6mm, 3c swa buried for about 18m with a 40A , B type breaker. If its XPLE its ok.

 

Is it OK?

 

If you are thinking about rating it for 90 deg C then the devices at the terminations MUST also be 90 deg C rated.

 

Almost, all are not.

 

SO, whilst the tabulated CCC of XLPE is higher than PVC this is due to the increased operating temperature, which is actually wasteful anyway due to the increased Joule heating losses over the life of the cable.

 

However, you cannot rate XLPE @ 90 deg, thus utilise the higher CCC in the tables unless, you can guarantee that the termination temperatures will be acceptable to the connected devices.

 

Most "normal" B type MCB's encountered only have a 70 deg C rating.

 

Now PVC is rated according to the BGB @ 38A for a 6mm buried direct or in underground duct.

 

How much is not buried, if 18m is?

 

If the buried section dominates then it may not be OK regardless whether it is PVC or XLPE.

 

If it was predominantly on traywork, then it would probably be OK regardless of the cable type.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

Terms of UseWe have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.