Lead Dressing - Page 1
Forum section: electronics / general

author: German_EE
author_rank: Super Contributor
timestamp: July 04, 2014, 01:16:37 pm
content: When setting up a workshop or lab the first advice we always receive is 'put in plenty of power sockets'. Well, fine, I've done that and my little workshop now has twenty five power sockets attached to an RCCD trip and a 50A breaker. There is however a problem.Most pieces of test gear come with an IEC socket on the back and a 6ft/2m power lead, the box is then put on the workbench 20cm away from the nearest power socket leaving a mess of cable. Add fourteen other pieces of test gear and that's a BIG mess of cable, so big that it's getting difficult to see the remaining mains sockets underneath the shelf. So, what do I do?a) coil up the spare bit of the power lead and put it behind the equipment?b) fold the spare bit of the power lead so that it's non-inductive and put it behind the equipment?c) drill holes in the back of the workbench and let the spare cable dangle down?d) cut the power leads to length and fit new power plugs?e) ........................................?All ideas welcome.

author: GreyWoolfe
author_rank: Unknown
timestamp: July 04, 2014, 04:52:52 pm
content: I wouldn't cut them. you never know if the equipment will end up being moved to a point that you wish you kept the extra. I typically coil the extra/wire tie in place and have never noticed a difference.

author: G7PSK
author_rank: Super Contributor
timestamp: July 04, 2014, 05:18:17 pm
content: Buy or make up some short leads.

author: XOIIO
author_rank: Super Contributor
timestamp: July 04, 2014, 06:31:32 pm
content: 25 sockets and you didn't put any near the workbench?

author: rob77
author_rank: Super Contributor
timestamp: July 04, 2014, 06:42:10 pm
content: i'm using 2 methods. - coiling up and making short power cords (saving the long ones for "later use" - ended up with a box full of later use power cords)

author: kolonelkadat
author_rank: Regular Contributor
timestamp: July 04, 2014, 07:04:45 pm
content: if you dont want to coil up the wires, you can make random "square waves" along the wall to take up the slack in the cables. pegboard is great for this. put some dowels in the holes and use them as corners for the "waves".

author: German_EE
author_rank: Super Contributor
timestamp: July 04, 2014, 08:59:38 pm
content: Ah! Now this is an interesting idea, I'll get some pegboard tomorrow and experiment.Oh yeah, the workbench has eight mains sockets, that should be enough for now.

author: IanB
author_rank: Super Contributor
timestamp: July 04, 2014, 11:03:24 pm
content: I'd suggest having two rows of power sockets. One row on the back of the bench for things that need to be plugged and unplugged in an ad-hoc manner for testing. Another row of sockets along the wall above the bench, say 1 m or more above the work surface. Use these for the items that will be plugged in all the time. That way the power cords will fall down neatly from above the bench and will not get in the way so much.If you don't have a lot of right-angle plugs, you might even put some of the sockets under a shelf facing downwards so the power cords don't have a bend in them.

author: David_AVD
author_rank: Super Contributor
timestamp: July 04, 2014, 11:06:46 pm
content: A 50A breaker on a single circuit?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 05, 2014, 12:07:46 am
content: ^ I was worried too.Maybe they are split further into different sub-circuits, with smaller breakers on each.

author: German_EE
author_rank: Super Contributor
timestamp: July 05, 2014, 06:47:45 pm
content: I must admit that I questioned the installation of that 50 amp breaker as well but it was pointed out to me that the feeder cable to the workshop area is rated at 60A. Amongst the devices are a 13.8V power supply that draws 8A peak and a linear amplifier in my ham radio station that draws 12A when on full power. There are also some power tools that have a surprising peak load figure such as a drill that draws 15A for the first 100mS of operation.As suggested though, I have subdivided the cables within the trunking and a local electrical inspector has passed my work as safe (my landlord insisted on this).

author: mamalala
author_rank: Unknown
timestamp: July 05, 2014, 07:10:49 pm
content: Quote from: German_EE on July 05, 2014, 06:47:45 pmDoesn't matter what the current capacity of the feed line is. What is important is what a single outlet can handle, and what the cable plugged into that can handle. Without extra breakers for the outlets this installation is extremely unsafe. Regular outlets are rated for 16 amps (i assume you are in Germany and installed Schuko outlets). The wiring to the outlets is very likely 1.5sqmm, which again is about 16 amps if it is not too long and not burried in some heat insulating material. Without a 16A breaker (max!) before that, you risk a nasty fire in case that part of the circuit is overloaded.Really, please fix that and install a sub-distribution box in the workshop. Let the heavy supply line feed that box, and in there split it up into separate 16A breakers/circuits, that in turn end up at the outlets. You can group 2 or 3 outlets for each 16A feed then. IIRC they even changed the codes a while ago, so that a 16A breaker is no longer allowed for outlets fed by a 1.5sqmm wiring, you would need to use 2.5sqmm instead.Greetings,ChrisEdit: this is of course assuming that the wiring is simply just split up, as described, with no additional breakers. If so, i'm wondering how an electrician could have given his OK to that.

author: German_EE
author_rank: Super Contributor
timestamp: July 06, 2014, 09:04:12 am
content: RelaxThere is a breaker box underneath one bench with two 16A and two 10A breakers in it and all of the bench wiring is 2.5mm. I could have gone into the entire electrical installation right at the start but the problem was sorting out the mess of cables behind the gear.Fortunately the pegboard idea works so I now have a clean work area. The inspector put a TÜV sticker on the breaker box before he left and that's one organization I'm not going to argue with.

author: SeanB
author_rank: Super Contributor
timestamp: July 06, 2014, 09:28:59 am
content: 16A on 1.5mm is not allowed here, you have to use a 10A breaker. For socket outlets to pass you need a minimum of 2.5mm cable up to a length limitation of 30m, then the cable size goes up. Irritating as all the old wiring at work is done to an older standard of 4mm cable, so for a lot of sockets that will not fit a 4mm cable in a daisy chain I have to pigtail each wire in the socket to 2.5mm for a 10cm length, and add an earth wire as the old wiring uses the metal conduit as earth. So far have only had 2 in wall faults, so ran surface wiring as the cabling will not pull out, and chasing out into 40 year old concrete is not going to happen.