My partner has suddenly got it in her head that running all the electrical wiring in the ceiling using  blue water pipe as a conduit is a great idea. This idea has come to her through a neighbor who has had it done for safety reasons, ie no chance of shorts through insect or animal activity.

We've lived in the house for 15 years without a problem, so my attitude is if it ain't broke, don't fix it.

What do you think, good idea, or not? Total cost 6000 baht.

Why not using the white or yellow PVC pipes. They are specifically for wiring. I'm guessing they are harder to ignite and maybe have some self extinguishing properties. 

@CLW beat me by milliseconds!!

 

The yellow or white PVC is actually intended for electrical, the bends available are more conducive to get cables in and, because it's thin walled (doesn't need to hold pressure) it "should" be cheaper.

 

Is your current wiring naked singles or muli-core sheathed?? If you don't have a creature problem, why fix it?

 

Our stuff that's in the ceiling spaces and not fixed to the wall is actually in flexy metal conduit as installed by sparky long ago.

 

EDIT Is your peaceful life + nookie worth 6k Baht? 

 

 

Waste of money.

Wires in free air can take more current than wires in pipe.

4 minutes ago, BritManToo said:

Waste of money.

Wires in free air can take more current than wires in pipe.

Really?🤔

We rewired the house about 7 years back and we put all of the wiring in electrical conduit. Really.  Up to you regarding how safe you want your residential wiring.  It didn't cost that much more and we did two houses. If I had to do it again, I'd do it again. 

16 minutes ago, Crossy said:

@CLW beat me by milliseconds!!

 

The yellow or white PVC is actually intended for electrical, the bends available are more conducive to get cables in and, because it's thin walled (doesn't need to hold pressure) it "should" be cheaper.

 

Is your current wiring naked singles or muli-core sheathed?? If you don't have a creature problem, why fix it?

 

Our stuff that's in the ceiling spaces and not fixed to the wall is actually in flexy metal conduit as installed by sparky long ago.

 

EDIT Is your peaceful life + nookie worth 6k Baht? 

 

 

It's not the money, It's possibly creating a problem you never had before.

19 minutes ago, Crossy said:

@CLW beat me by milliseconds!!

 

The yellow or white PVC is actually intended for electrical, the bends available are more conducive to get cables in and, because it's thin walled (doesn't need to hold pressure) it "should" be cheaper.

 

Is your current wiring naked singles or muli-core sheathed?? If you don't have a creature problem, why fix it?

 

Our stuff that's in the ceiling spaces and not fixed to the wall is actually in flexy metal conduit as installed by sparky long ago.

 

EDIT Is your peaceful life + nookie worth 6k Baht? 

 

 

Ditto!

33 minutes ago, giddyup said:

40 minutes ago, BritManToo said:

Waste of money.

Wires in free air can take more current than wires in pipe.

Really?

 

It's true because they dissipate heat better if they're not in a conduit.  Of course, that's not the only deciding factor.  Especially if you have vermin that chew on exposed wires.

 

 

36 minutes ago, giddyup said:

43 minutes ago, BritManToo said:

Waste of money.

Wires in free air can take more current than wires in pipe.

Really?🤔

Absolutely, in free air the heat induced by the current can dissipate easily.

That is why the power rating is different for wires in conduit (about 20%) compared to wires clipped to walls etc.

51 minutes ago, giddyup said:

Really?🤔

2.5mm twin 20a max in conduit, 27a max in free air.

A fairly significant difference.

1 hour ago, Crossy said:

Is your current wiring naked singles or muli-core sheathed?? If you don't have a creature problem, why fix it?

 

My 2 cents.  Just because you don't have vermin today doesn't mean you never will.  For $175 USD, (6K Baht) I'd pull that trigger.  And not worry about that rustling sound in the attic later.

 

Edit:  That's after checking the ampacity in conduit and being sure that's not going to cause an unintended consequence.  If you need to upsize the wire, that may blow the budget.  Sadly, all my ampacity charts are based on the NFPA published NEC and AWG wire.  (Yank stuff)  Not metric.  I'm sure someone here has an mm2 chart.

 

 

 

20 minutes ago, impulse said:

 

My 2 cents.  Just because you don't have vermin today doesn't mean you never will.  For $175 USD, (6K Baht) I'd pull that trigger.  And not worry about that rustling sound in the attic later.

 

Edit:  That's after checking the ampacity in conduit and being sure that's not going to cause an unintended consequence.  If you need to upsize the wire, that may blow the budget.  Sadly, all my ampacity charts are based on the NFPA published NEC and AWG wire.  (Yank stuff)  Not metric.  I'm sure someone here has an mm2 chart.

 

 

https://www.doncastercables.com/technical-help/

 

2 minutes ago, Crossy said:

https://www.doncastercables.com/technical-help/

 

Thanks for that. 

 

One additional suggestion I have is to measure the diameter your wire (conductor) with a caliper.  Not all markings are honest.  Some, not even close.

 

 

 

1 hour ago, sometimewoodworker said:

Absolutely, in free air the heat induced by the current can dissipate easily.

That is why the power rating is different for wires in conduit (about 20%) compared to wires clipped to walls etc.

Does this different power rating affect power to appliances etc?

1 hour ago, impulse said:

 

My 2 cents.  Just because you don't have vermin today doesn't mean you never will.  For $175 USD, (6K Baht) I'd pull that trigger.  And not worry about that rustling sound in the attic later.

 

Edit:  That's after checking the ampacity in conduit and being sure that's not going to cause an unintended consequence.  If you need to upsize the wire, that may blow the budget.  Sadly, all my ampacity charts are based on the NFPA published NEC and AWG wire.  (Yank stuff)  Not metric.  I'm sure someone here has an mm2 chart.

 

 

 

This work would be done by local Thais, how qualified or experienced they are to do things like check ampacity, I don't know.

1 hour ago, BritManToo said:

2.5mm twin 20a max in conduit, 27a max in free air.

A fairly significant difference.

Are there any consequences to this?

1 hour ago, giddyup said:

Does this different power rating affect power to appliances etc?

It affects the maximum power available on a circuit before it gets too warm. So decide on the maximum power you want to use and then make sure you have enough circuits for the load. Things like instant water heaters and AC’s should have dedicated circuits and for water heaters 4mm cable at least

What kind of wire do you have installed currently? Are they single wires of different colours or are they sheathed twin and earth type cable? It's normal to put the single wires in some form of conduit. As it's been suggested use the white or yellow PVC pipes. They have a thinner wall than the blue water pipe which makes them easy to bend with a spring tool and all the other accessories and attachments are designed for those pipes. The white pipe is thinner and comes in 2.4m lengths. The yellow is a bit thicker and comes in 4m. I like the white pipe as you can have a slightly shallower wall chase when burying the conduit in the wall but that's not relevant in your case.

 

Back to current carrying capacity, this seems to be a popular method..

 

4-6 conductors: Derate by 80%. 

7-9 conductors: Derate by 70%. 

10-20 conductors: Derate by 50%

 

This is for unsheathed THW single cables (which is what I'm assuming you have). You don't include the earth/ ground cables in the calculation, only current carrying conductors. Thai Yazaki 2.5mm2 THW cable is rated to 28A in free air. Bangkok Cable 2.5mm2 THW is rated to 29A. So if you had 2-3 circuits of the former (4-6 current carrying conductors) in a single conduit the rating would fall to 22.4A. Which is still fine on a 16 or 20 amp circuit. So don't put too many circuits in one single conduit. You check the current rating of the wire by first finding out the cross sectional area (e.g. 2.5mm2, 4mm2, 6mm2 etc.) and then checking on the manufacturers website but they should all be pretty similar. Check out the tables in the links below.

 

https://thaiyazaki-electricwire.co.th/images/productindustrial/_2021101206531260227 IEC 01 THW.pdf

https://www.bangkokcable.com/system/product/file_upload/210531_450!750V 70C 60227 IEC 01 (THW)-REV 04.pdf

 

10 hours ago, Jurghh said:

4-6 conductors: Derate by  to 80%. 

7-9 conductors: Derate by to 70%. 

10-20 conductors: Derate by to 50% (though semantically in this case “by” and “to” are the same

There is a significant semantic difference required to the above, as the meaning of the post would mean 

4-6 conductors: Derate by 80%.  = 20% of rating

7-9 conductors: Derate by 70%.   = 30% of rating

10-20 conductors: Derate by 50%   = 50% of rating

this is an obvious mistake 

On 4/25/2025 at 4:48 PM, giddyup said:

My partner has suddenly got it in her head that running all the electrical wiring in the ceiling using  blue water pipe as a conduit is a great idea. This idea has come to her through a neighbor who has had it done for safety reasons, ie no chance of shorts through insect or animal activity.

We've lived in the house for 15 years without a problem, so my attitude is if it ain't broke, don't fix it.

What do you think, good idea, or not? Total cost 6000 baht.

Conduit for electrical wiring in the ceiling is a good idea - especially if you've got rats in the ceiling constantly eating the plastic around the cable, but there is yellow conduit widely available for this purpose and it is much cheaper than blue plastic (for water) pipes. Then again (thinking about my comment - sorry), maybe the rats can eat the yellow conduit as it isn't that thick - like the heaviest version of 12mm blue plastic water pipe?

6 hours ago, sometimewoodworker said:

There is a significant semantic difference required to the above, as the meaning of the post would mean 

4-6 conductors: Derate by 80%.  = 20% of rating

7-9 conductors: Derate by 70%.   = 30% of rating

10-20 conductors: Derate by 50%   = 50% of rating

this is an obvious mistake 

I didn't notice that. Yes you are correct. Thanks

On 4/25/2025 at 4:48 PM, giddyup said:

My partner has suddenly got it in her head that running all the electrical wiring in the ceiling using  blue water pipe as a conduit is a great idea. This idea has come to her through a neighbor who has had it done for safety reasons, ie no chance of shorts through insect or animal activity.

We've lived in the house for 15 years without a problem, so my attitude is if it ain't broke, don't fix it.

What do you think, good idea, or not? Total cost 6000 baht.

Blue = water

Yellow, white or grey = electric, I doesn't really matter to yo only who follows your work for repairs. Cutting into a blue pipe thingking its water could have disasterous consequences