Wiring to a detached Garage for Arcade Machines

[Rallyace]

Hi,

I am new to the forum. I have a a detached garage which is about 2 meters away from the house. It currently has a single double socket with a single 2.5 cable running back to the CU in the House. Due to the fact I am running several arcade machine in the garage and really need 6 double sockets, I want to run a new ring in the garage. I have 2 new 2.5 cables run under the floor in the house from the CU ready to be connected to a 32a RCD.

A couple of questions

1.Do I need to switch to Amoured cable to run the 2m underground between the House and the garage or can I use a suitable conduit? If so would Adaptaflex Liquid Resistant Covered Steel Conduit be suitable?

2. Do I need any additional protection or is the 32a RCD at the consumer unit in the house ok? The garage is only a couple of meters from the house.

 

[Deleted member 26818]

The steel conduit would be suitable.
The RCD at the house will provide protection for both the socket-outlets and for the cables if required.

 

[bomjac]

Hmmm, arcade machines. Tell me more.

I have been watching the 2nd hand arcade sales on ebay for several years now. Much to my dismay they seem to have dried up recently. The closes I ever got to actually bagging one was about 2 years age. 2nd hand Defender cab (not working) that I missed the closing bids on due to an argument with Mrs Bomjac. £120 it went for, absolutely gutted that day.

 

[Rallyace]

Have a look on Welcome to Jamma+ - Video Arcade Gaming Community & Forum. You need to make a few posts before you can see the "For Sale" section, but it's normally much cheaper than ebay and you will find lots of good advice available in the forum.

 

[Rallyace]

I have had a builder in to insulate the garage and install the cabling and back boxes for the ring main. The cables have been run in the gap between the wall and insulated plasterboards The cable is tacked in some places and lose in others, the walls are lined with Gyproc Thermaline Plus which has a extruded polystyrene backing. The data sheet states:-
Stability and Reactivity No special physical conditions need to be avoided. No specific restrictions regarding incompatible materials.
However it is still a type of polystyrene and I can find no information anywhere regarding this type of insulation and PVC cable.

The builder said the Gyproc Thermaline Plus board with the backing would be to heavy for the ceiling and sugested the foil backed plasterboard with a separate insulation. I didn't know it was going to be low density polystyrene until it turned up as I had asked the builder to get what he thought was best. The joists are 100mm deep and the polystyrene is 50mm leaving a 50mm air gap above with some additional vents installed to allow air to circulate. Four cables have been run in the gap above the polystyrene three for lighting (2 switch and 1 feed) and one cable across the garage to complete the ring main. These are run through the joists at a 75mm, but I am now nervous that any slack may be touching the polystyrene or that any lose polystyrene may find it's way onto the cable. I did ask the builder several times if the cable should be run in conduit to avoid contact with the polystyrene and was that it was better to not to. Unfortunatly this has all now been plastered in and having read about the effect of polystyrene on PVC cables I am now really worried that this is not safe. The information I have read on the subject seem to be conflicting. The dangers are very poorly publicised and I could find nothing on either products website! What are my best options as I don't want to destroy all the work that has been done as it has not been cheap.

Questions

1 Is it just the four cables that have been run near the low density polystyrene that is at risk or is the cable behind the Gyproc Thermaline Plus also at risk?

2 Can I pull through an alternative type of cable that is not affect by the polystyrene so I don't have to destroy all the insulation and plaster work? Voltimum states that Saffire OHLS cable can be used, but is this available?

 

[Deleted member 26818]

My understanding, is that over time the plasticiser from the cable will be leached out. Making the cable insulation brittle and hard.
Not really a problem, unless you intend moving the cable.

 

[Engineer54]

Rallyace,

My understanding, is that modern polystyrene used for roof insulation does not now affect PVC cables as it used too. Manufacturers changed the chemical make up some years ago now, but old ways and habits still prevail...lol!!

For piece of mind, use a bit of off-cut cable and some of your insulation material and tape together tightly. Leave together for a couple of weeks or so, before checking for any signs of reaction between the two materials. You may be unlucky and have some cheaper imported stuff, but other than that you should be OK....