Is this a white painted brick utility room?
If the wall is bare...
- Fit 20mm Round Conduit to the wall
- Conduit shall be continuous AND erected before cables drawn in
- Draw in dual 2.5mm or single 4mm 6491X from the ring
Continuous means just that - 6491X is unsheathed.
Alternatively instead of using conduit you could use a surface run cable such as FP200 or BS8436 in white clipped to the wall. Their sheath is slightly tougher (medium impact rating) than conventional PVC flat-twin-&-earth and acceptable run on the surface in domestic (AG2).
If the wall is plastered...
- Create a chase in the plaster
- Fit in dual Oval Conduit or Capping
- Run dual FTE 2.5mm from the ring
What is the point of Conduit or Capping under plaster?
- #1 - to protect from the plasterers trowel
- #2 - to permit cable replacement without removing plaster
Obviously for #2 to be possible the conduit/capping would need to be a straight run be it vertically or horizontally between a) floor/ceiling & wiring accessory or b) wiring accessory & wiring accessory. Old capping was sized too tight to the cable making it difficult to remove cable if the wall is bellied outwards (bricks pinch cable against capping), modern capping is a little more generous but the problem can still remain - avoided by either channelling or use of oval conduit.
Generally domestic does not use 20/25mm round conduit much - BR "A" limit a chase to 16mm for a cavity wall leaf.
If the utility room will get a washer & dryer...
1 - Ring should remain balanced That is the load in each "leg" of the ring should be balanced rather than at one end. An imbalanced ring would be where one "leg" of the ring is 6m from the CPD whereas the other "leg" is 25m from the CPD - the load would be unevenly balanced between the two legs.
2 - Washer & Dryer should not be in the same double socket A double socket is 19.5A continuous rating, whilst a washer & dryer DO cycle their elements modern washers are "cold fill" so heat water for longer and a dryer can be running for quite some time in a busy familly. So it can be better to plug them into separate 13A sockets.
3 - Ideally I would run twin 20A radials for each of dryer & washer Some may prefer a dedicated 32A ring because otherwise if one 20A radial trips someone will no doubt try to plug both appliances into the remaining 20A radial which can be a short-lived solution :-)
If this is a "bare brick" utility room with surface wiring I would run twin 20A radials back to the CU in FP200-variant or BS8436. You could run two 13A radials spurred off the ring via SFCU, depends on whether that makes cable routing any easier.