basket tray

[cliffed]

Your feelings please,we,ve got a real gud job,1st fixin up to 32 hotel bedrooms,the only down side is this.Basket tray thru out the roof space,ok,then running plastic pipe to all electric points.This piping needs to be bac to the basket tray,the cabling specified is 2.5 fp,due to volt drop etc.Can u actually think that we r goin 2 pull fp cabling into a 25mm pipe,this pipe wiill go into the roof space 2 the tray,the difficulty is the lenght of piping & the bends 2 get 2 the tray,3-4 meters of pipe & if lucky only 2x45,s,.THe designer wants a fully re-wireable system,wat happened 2 the gud old conduit & trunkin days,your comments much appreciated, ta ra bab

 

[grantr37]

The designer (not mentioning or implying any particular company or names here)is maybe trying to take the psss they dont have a clue, that set up is silly, it is in no way rewireable and will never pass the building standards for a Hotel either, or a Fire safety survey before sign over/handover.....not a chance.....it has to be fully done in singles and metal conduit/Trunking for ALL mains power, the fire Alarm and Telephone/Data and CCTV can be done in plastic conduit but NOT the mains supplies....the designer has just decided that basket can get thrown in with a set of bolt cutters and one of those clip bending tools...and thinks that a quick chop with a hacksaw and a bit of solvent cement will allow for a quick throw in of (plastic) containment....
What if the cores get damaged, the Aluminium conductors dont like being bent too much in FP......and what about 3 Phase supplies for the ventilation and other things...and heavier loads such as long corridors full of lights...and the Earthing standards....?????.....FP is ok for small lighting circuits with a small load, and for fire exit signs etc.....but not for sockets....it has different properties than copper singles and is not really suited to continuous loading...

If it gets an inspection prior to hand over, it will fail and they will tell you to rip out the walls and do it all again.....in metal and singles....I have seen this happen one time before in a Hospital building and the walls were all painted up and everything....it was "get it out now" and they spent 3 weeks re-doing the whole floor of the building.....cost something like 70 grand when you take into account the fine that they got as per contract for late final hand over/completion...although that was an NHS inspection team from the head estates office who were going round everything with a magnifying glass...maybe the customer wants that but I doubt it...

 

[malcolmsanford]

Aluminium conductors ??

Did I miss this part of the thread.

 

[ricardo123]

I agree. It may be worth asking the designer whether he meant XPLE and not fp. If I wanted it rewireable I would specify singles in conduit and trunking.

The only place where I have seen fp used electrically is the supply to the fire alarm spur which please correct me if I'm wrong is what the fire alarm guys prefer you to do.

 

[mogga]

Why shouldnt TWE be used grant??? Iv been testing hotels recently and they are all TWE except os lighting AC fans switchrooms All rooms are TWe what "Standard " does this break ?? Senior Member

Join Date Jan 2011 Posts 397 Thanks 122 Thanked 42 Times in 36 Posts

Re: basket tray

The designer (not mentioning or implying any particular company or names here)is maybe trying to take the psss they dont have a clue, that set up is silly, it is in no way rewireable (How does this matter??)and will never pass the building standards for a Hotel either( Where is this information?), or a Fire safety survey (A What?)before sign over/handover.....not a chance.....it has to be fully done in singles and metal conduit/Trunking for ALL mains power,( WHO Says?) the fire Alarm and Telephone/Data and CCTV can be done in plastic conduit but NOT the mains supplies....the designer has just decided that basket can get thrown in with a set of bolt cutters and one of those clip bending tools...and thinks that a quick chop with a hacksaw and a bit of solvent cement will allow for a quick throw in of (plastic) containment....
What if the cores get damaged, the Aluminium (???) conductors dont like being bent too much in FP......and what about 3 Phase supplies for the ventilation and other things...and heavier loads such as long corridors full of lights.)Now normaly LEDs or small flourys)..and the Earthing standards....?????.....FP is ok for small lighting circuits with a small load, and for fire exit signs etc.....but not for sockets..( Most tescos use 4mm FP for sockets as clipping to purlin looks better than TWE and loading charecteristics are BETTER than TWE)..it has different properties than copper singles and is not really suited to continuous loading...

If it gets an inspection prior to hand over, it will fail and they will tell you to rip out the walls and do it all again.....in metal and singles....I have seen this happen one time before in a Hospital building and the walls were all painted up and everything....it was "get it out now" and they spent 3 weeks re-doing the whole floor of the building..( The reason for this is probably down to job SPEC by client and the contract designer not adhearing to it )...cost something like 70 grand when you take into account the fine that they got as per contract for late final hand over/completion...although that was an NHS inspection team from the head estates office who were going round everything with a magnifying glass...maybe the customer wants that but I doubt it...​

 

[ecclescake]

TWE? Is that Twin With Earth.

 

[mogga]

yes twe

 

[bugsy]

Why shouldnt TWE be used grant??? Iv been testing hotels recently and they are all TWE except os lighting AC fans switchrooms All rooms are TWe what "Standard " does this break ?? Senior Member

Join Date Jan 2011 Posts 397 Thanks 122 Thanked 42 Times in 36 Posts

Re: basket tray

The designer (not mentioning or implying any particular company or names here)is maybe trying to take the psss they dont have a clue, that set up is silly, it is in no way rewireable (How does this matter??)and will never pass the building standards for a Hotel either( Where is this information?), or a Fire safety survey (A What?)before sign over/handover.....not a chance.....it has to be fully done in singles and metal conduit/Trunking for ALL mains power,( WHO Says?) the fire Alarm and Telephone/Data and CCTV can be done in plastic conduit but NOT the mains supplies....the designer has just decided that basket can get thrown in with a set of bolt cutters and one of those clip bending tools...and thinks that a quick chop with a hacksaw and a bit of solvent cement will allow for a quick throw in of (plastic) containment....
What if the cores get damaged, the Aluminium (???) conductors dont like being bent too much in FP......and what about 3 Phase supplies for the ventilation and other things...and heavier loads such as long corridors full of lights.)Now normaly LEDs or small flourys)..and the Earthing standards....?????.....FP is ok for small lighting circuits with a small load, and for fire exit signs etc.....but not for sockets..( Most tescos use 4mm FP for sockets as clipping to purlin looks better than TWE and loading charecteristics are BETTER than TWE)..it has different properties than copper singles and is not really suited to continuous loading...

If it gets an inspection prior to hand over, it will fail and they will tell you to rip out the walls and do it all again.....in metal and singles....I have seen this happen one time before in a Hospital building and the walls were all painted up and everything....it was "get it out now" and they spent 3 weeks re-doing the whole floor of the building..( The reason for this is probably down to job SPEC by client and the contract designer not adhearing to it )...cost something like 70 grand when you take into account the fine that they got as per contract for late final hand over/completion...although that was an NHS inspection team from the head estates office who were going round everything with a magnifying glass...maybe the customer wants that but I doubt it...
​

Since when has FP had aly conductors? why cant it be used for small power installations
what about the cpc its the same size as the line conductors and nearly all diocese insist on all installations in FP or MICC

 

[mister]

Twin & earth in commercial premises is poor IMO, it is a domestic product complete with an undersized CPC, lets just hope the Ze isn't too low!

I know its widely used but that does not make it right.

 

[mogga]

Twin & earth in commercial premises is poor IMO, it is a domestic product complete with an undersized CPC, lets just hope the Ze isn't too low!

I know its widely used but that does not make it right.

What makes it wrong??? as most jobs are done on a budget notmany firms use trunking and galv conduit these days unless its specified makes jobs quicker hence price lower and shops ofices ect open earlier

 

[mister]

What makes it wrong??? as most jobs are done on a budget notmany firms use trunking and galv conduit these days unless its specified makes jobs quicker hence price lower and shops ofices ect open earlier

Not necessarily wrong, Depending on the Ze as I said.

Too many times a budget is used as an excuse for poor design, in most cases outside domestic twin & earth is the wrong choice.

 

[IQ Electrical]

Not necessarily wrong, Depending on the Ze as I said.

Too many times a budget is used as an excuse for poor design, in most cases outside domestic twin & earth is the wrong choice.

What a crazy statement!

Of course a budget influences design, it's only when it affects compliance that there's a problem!

 

[mister]

I don't recall saying budget does not influence design, simply that it was often used as an excuse for poor design, if design is poor what's the chances that any effort has been put in to compliance?

 

[IQ Electrical]

I don't recall saying budget does not influence design, simply that it was often used as an excuse for poor design, if design is poor what's the chances that any effort has been put in to compliance?

Poor design being the use of T&E cable outside of a domestic environment?

In the vast majority of shops and offices, how is the use of T&E cable tantamount to poor design?

Is the adiabatic equation applied differently in domestic installations?

Are external influences prohibitive outside of the domestic environment?

Each installation is assessed on an individual basis and to that extent, I completely disagree with your sweeping statement.

 

[mogga]

I don't recall saying budget does not influence design, simply that it was often used as an excuse for poor design, if design is poor what's the chances that any effort has been put in to compliance?

Thats a bit of a sweeping statement to make there Last install job I did has 2 parts on the job Landlords supplies (staircase and 1 office) and a full 3 floor bank including 2MCCB panels AC power and lighting to all floors and lift Landlords was started before the bank had 4 men on each job Landlords was all trunking and galv conduit Both jobs were completed at same time with the landlords having loads of problems due to miss marking of singles and emlighting ,main lighting being crossed several times the Bank(our job) completed on time IN Budget and tested perfectly ( bar 1 circuit of lighting due to celing fixers cutting a cable n not informing anyone) I know which contractor Id prefer to work with again

 

[mister]

Poor design being the use of T&E cable outside of a domestic environment?

In the vast majority of shops and offices, how is the use of T&E cable tantamount to poor design?

Is the adiabatic equation applied differently in domestic installations?

Are external influences prohibitive outside of the domestic environment?

Each installation is assessed on an individual basis and to that extent, I completely disagree with your sweeping statement.

In the vast majority of shops and offices T& E is thrown around like data cable not clipped / supported, laying on ceiling grids, tie wrapped to conduits....

Does the use of twin and earth in areas with low Ze (such as a building with a private supply) comply using 54.7 or the Adiabatic?

I would suggest that if one is looking at com/ind installations and arriving at T&E, its time to re-asses.

I accept that in some cases outside domestic it is / maybe the correct choice, but they are extremely limited.