Do you connect multiple extension blocks?

[laserblazer]

I know it's no ideal but we have one classroom where the only available power point is 10 metres from the teacher's desk. I have run a heavy duty single extension lead to the desk and connect a 4-way extension lead to that. The maximum load is around 2.5A. Our HSO picked up on it during her annual inspection and says it is "overloaded".

 

I do believe it is bad practice to extend extensions but I don't know what the regulations say. Can anyone help please?

[srochford]

the first computer room I had used 24 BBC Computers and monitors a printer and various other bits all fed from a single power socket and a lot of 4 way adpators ...

 

It's certainly not overloaded in terms of power drawn and I wouldn't see it as a risk (unless the wires could be a trip hazard).

 

If the HSO is just concerned about the use of 2 extension leads, then just get a 4 way block with a 10m lead. There is more risk of overheating every time you include an extra plug/socket pair (the brass springs and pins never make perfect contact and as the oxide layer builds with age, the resistance increases and the temperature will rise slightly)

 

What are the chances of getting a properly wired socket in the room? If you have an in-house electrician it's a fairly small task but if you have to bring in a contractor it's probably prohibitively expensive.

[GrumbleDook]

As Steve said, the risk is not the load (usually) but the number of connections.

 

A single extension used to feed a four-way is a reasonable risk (as long as neither lead is coiled ... coiling power leads is a major risk which is why you should never use a reel extension lead for a long term connection) but if you can eliminate it to keep them happy I would do so.

 

HSOs are a funny bunch and even pick up things that Fire Safety Officers would classify as 'reasonable'!

[laserblazer]

Thanks,

 

The 10m stretch is clipped to the wall. I have reported to the HT that in my opinion it is safe but that in an ideal world we should install additional powerpoints. We don't have an in-house electrician so we would need to call in contractors ata a cost.

[Andrew_C]

I've read that "the indiscriminate use of 4 ways is deprecated". I think it was a fire brigade document. Now, you are not using them "indiscriminately", you are considering how it will be used, assessing the risk, and only using them if that risk is appropriately low.

 

The load on them is very low, so contact heating, even if daisy chained, will be negligible. The long one is clipped to the wall thus allowing plenty of cooling. You say the long lead is "heavy duty" does this mean large conductors (>1.5mm2) or thick insulation. Shouldn't matter but you do need to think about the earth loop if you start using long leads. 10m isn't really long in this context, 20+m is.

 

To reduce the risk of high current draw, which would be an "indiscriminate use" I've marked several as "NO HEATERS" and reduced the fuses to 5A. If they blow the fuse they have to explain what part of "No Heaters" they don't understand.

 

Most if not all HSOs need hitting with a large "clue bat" when it comes to electrics; it is just so far outside their "have I ticked the box to allow me to get out of bed" mentality.