Discuss Saddle / Fixing Spacings in the Electrical Forum area at ElectriciansForums.net

Patryk

New EF Member
Messages
2
Location
Birmingham
Hello guys. This is my first post so go easy on me.

I have had a install job at the company I work for currently. It is pvc 20mm conduit run on the wall horizontally. Seeing that the 18th edition in reg (521.10.202) Note 3 says that plastic clips are not meant to be used as a sole means of support and suitably spaced metal fixings should be used. So for the sake of this argument and this installation, we are using all metal saddles. My confusion begins that according to my supervisor the saddles are meant to be spaced at 250mm apart and no more then 150mm from a bend. I referenced back to the onsite guide Appendix D, Table D3 which says that distance between supports (metal saddles) for 20mm Rigid Insulating (PVC) should be be no more then 1.5m Horizontally and 1.75m vertically. Note B mentions clips should be no further then 300mm from a bend.

I have heard from various sources that the spacing should be 250mm between the saddles. My question is, am I right to think that the spacings they are using is unnecessary or are they correct. If so, what regulation specifically says this and/ or what table shows this. I really want to do my work correct but I also want to be able to reference it back and understand it.

Thanks in advance guys
 

Ian1981

Forum Mentor
Messages
2,975
Location
North east
Hello guys. This is my first post so go easy on me.

I have had a install job at the company I work for currently. It is pvc 20mm conduit run on the wall horizontally. Seeing that the 18th edition in reg (521.10.202) Note 3 says that plastic clips are not meant to be used as a sole means of support and suitably spaced metal fixings should be used. So for the sake of this argument and this installation, we are using all metal saddles. My confusion begins that according to my supervisor the saddles are meant to be spaced at 250mm apart and no more then 150mm from a bend. I referenced back to the onsite guide Appendix D, Table D3 which says that distance between supports (metal saddles) for 20mm Rigid Insulating (PVC) should be be no more then 1.5m Horizontally and 1.75m vertically. Note B mentions clips should be no further then 300mm from a bend.

I have heard from various sources that the spacing should be 250mm between the saddles. My question is, am I right to think that the spacings they are using is unnecessary or are they correct. If so, what regulation specifically says this and/ or what table shows this. I really want to do my work correct but I also want to be able to reference it back and understand it.

Thanks in advance guys
There’s guides for each spacing but ultimately I’d go with the manufacturers recommendations.
 

davesparks

Forum Mentor
Messages
12,817
Location
guildford
250mm sounds ridiculously close to my mind.
On the rare occasions I use plastic conduit I've always worked to 1m spacings,
 

Dave OCD

Forum Mentor
Messages
3,165
Location
Cornwall
I tend to go for around 600mm vertically and a bit less horizontally with 20 and 25mm pvc but that's just me. 250mm is ridiculous though !
 
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JeanGenie

Regular EF Member
Messages
66
Sounds to me like they're getting the distances confused with flexible conduit (copex). 250mm spacings on plastic would look stupid.
 
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Patryk

New EF Member
Messages
2
Location
Birmingham
Is this inside or outside.
This is ran outside but over a roofed wall so direct contact with rain wont be an issue, running at a height of 2m. This is also a communal area for 2 flats. Regarding what the circuit is for.... it is meant to provide emergency lighting to the emergency escapes of both flats and to the emergency outside staircase. It also provides emergency lighting to an outside corridor with a roof that leads around the front of the house. PVC is not ideal and I do realise as it expands and contracts under hot/ cold conditions but this is what has been requested.
 

westward10

In echoed steps I walk across an empty dream.
Staff member
Moderator
Messages
11,549
Location
Northamptonshire
I would be more liberal with the fixings if it is external as the temperature fluctuations can cause the tube to deform if slip joints are not employed.
 

Dustydazzler

Regular EF Member
Messages
1,036
Location
Surrey
I do 300mm (one hammer length) for external plastic tube , it helps prevent dandy droopy conduit

Inside I would just do what ever the OSG states
 

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