Grounding question on power strip

[Goodizzy]

Hello,

I am located in the US but have an affinity for older UK valve equipment. I recently purchased a metal, rackmount power strip to put into a studio cabinet for handling all my 240v equipment after the step up transformer. Previously I had used with success a cheaper plastic strip that worked fine.

The item had the label in the picture on it and I am a little confused as to the 'earth connection before connection supply' line? I am not familiar with Euro or UK grounding standards so maybe someone could shed some light? I would be much obliged.

[turretslug]

The statement "high leakage current" implies that there are suppression capacitors between the supply wires and the earth wire, i.e.the casing of the strip and that if the strip wasn't earthed securely before the application of supply voltage, it could float up in potential from ground, possibly presenting a shock hazard.

Do you know the values of the internal suppression components?- some situations use relatively high capacitance values that would be inappropriate for other usage.

[eaglework]

Could also be the case that the earth pins of the individual mains outlets are not connected to the incoming mains earth - this enabled the equipment in rack to use the rack earth and not the incoming mains earth. Does the PDU have a separate earth connection?

[dseymo1]

This appears to be a Chinese-made item (see here: https://turn-link.en.made-in-china.c...th-Switch.html), which may not follow standard UK practice. Indeed, there is very little 'land' around the recepticles, suggesting a risk of body contact with the plug pins.
I can't find anything to suggest internal suppression, but would strongly suggest dismantling the strip and checking for continuity of grounding between the cord and the sockets, and with the body of the strip.

[Goodizzy]

Thanks for the replies. The enclosure only opens on the ends and the back seems unable to get off so I had to peer down the narrow body cavity with a flashlight.

I didn't see any suppressor caps unless they were in the molded mains plug, which appears to be euro standard plug. ( I have an adapter to fit the US outlets from my other strip). All safety grounds on the sockets connect to the incoming mains safety ground, with the far end earthed to the power strip housing.

I wasnt aware this was Chinese as my girlfriend ordered it for me, but upon closer inspection the bus bars connecting the sockets look too small a gauge for a 15A rated load. I may end up just returning this and trying to find something better. Much obliged for all the help.

[turretslug]

If there are no visible suppression components, then the label might just be a cut-and-paste listing job that gets printed on a lot of their products as a "cover ourselves" tactic. Apart from the shock hazard (TBH, more likely a tingle hazard with responsibly chosen capacitors), another problem can arise when lots of filtered distribution panels/appliances are used together in that the normally low leakage currents can add up to enough leakage to cause nuisance tripping of residual current breakers.

Trouble with the container-loads of everything imaginable coming out of China is that some of it is very good, some is simply horrible and much is somewhere in between!

[MrElectronicman]

If it is anything like a US power strip I bought recently, the buss-bars? connecting the outlets are just bare wires, not good at 120 volts, but very dodgy at 240 volts

[Refugee]

I have seen a lot of those power strips fitted with 10 amp fuses and clearly marked 10 amps even from UK stores such as Wilco.
I am careful not to load any of them at more than 6 amps.
Old power strips used to be rated at 13 amps and used to get very hot on full load.

[McMurdo]

unlikely to meet any british standards if that's the strip you've got. Think twice before connecting it to a 240V supply. If it landed in the UK it would have been imported illegally.

[Goodizzy]

With all of my 240V equipment connected and running full load, I'm probably not looking at more than about 2.5A, but the construction of the strip made me second guess it. (Buss bar not the appropriate term but the best way to describe the shoddy workmanship)

Does anyone have a suggestion for something similar and safe? I don't mind paying VAT...
My only caveat being rackmountable.

[Diabolical Artificer]

I'd recommend these lads - http://www.penn-elcom.com/Default.as...C=Search&LG=EN proper rack mount PDU's with a US website - https://www.pennelcomonline.com/us/us/Home.aspx

Andy.

[dseymo1]

Highly recommended, and more-or-less an industry standard, but not cheap:
https://olsondirect.co.uk/5-way-13a-...-plug-pdu.html
Edit: The 'old school' alternative is to use MK Metalclad sockets on a home-made backbox. For a really neat job, MK do panel-mount bare sockets in a similar style.

[karesz*]

Hi Goodizzy,
For some quality Rack-solutions I would select Rack-Powerstrips from some professional producer as Knürr, Vertiv Emerson Power Distribution[/URL], Schroff or even Rittal...
Rgds, Karl

[Radio Wrangler]

It is likely that your step-up transformer is wound as an autotransformer which gives no isolation between the 110v input service and the output. Which end of your 110v connection is near ground may not be certain, and the auto transformer can create a larger than expected voltage between one of the two 240v connections and ground. So the current through filtering capacitors can be larger than expected. This can give you problems with ground leakage-sensing protection trips.

David

[Craig Sawyers]

Originally Posted by Refugee

I have seen a lot of those power strips fitted with 10 amp fuses and clearly marked 10 amps even from UK stores such as Wilco.
I am careful not to load any of them at more than 6 amps.
Old power strips used to be rated at 13 amps and used to get very hot on full load.

That is true. I've seen such things either discoloured brown or physically warped. They can be a total nightmare.

Recently I've taken to making my own, with switched high quality MK double wall sockets, plastic back plates, screwed to a wooden board and wired internally with twin and earth. No heating problem with those!

Craig

PS just noticed that dseymo1 recommends the same thing!

[dglcomp]

There is this from Thomann that would do the job https://www.thomann.de/gb/the_t_racks_power_7_s_gb.htm

Rated for 15A (I'm guessing not using the fitted 13A plug ) so a bit of a safety margin included.

€21.01 + €30 shipping to USA without tax.

Haven't used it myself but have always been happy with Thomann own brand stuff.

[TonyDuell]

Originally Posted by dseymo1

Highly recommended, and more-or-less an industry standard, but not cheap:
https://olsondirect.co.uk/5-way-13a-...-plug-pdu.html
Edit: The 'old school' alternative is to use MK Metalclad sockets on a home-made backbox. For a really neat job, MK do panel-mount bare sockets in a similar style.

I was going to recomend Olson, but you beat me do it. The only disadvantage to them is the price. I have a couple that I unscrewed the rackmounting brackets from and use as free-standing extension leads. A lot safe I feel than some of the no-name leads on sale now.

Incidentally, the (old) Olson units I have here use MK panel mount sockets on a metal panel.

[McMurdo]

I think I have quite a few Olsen or similar ones but they use Wandsworth sockets. Much better job all round.