UNI-T UT230B UK Power Meter - Dangerous design. - Page 1
Forum section: electronics / general

author: TheBay
author_rank: Unknown
timestamp: October 17, 2018, 01:11:41 pm
content: I bought a UNI-T UT230B-UK Power meter as I wanted to check approximately the power use of some devices and also handy when repairing things to see quicklywhat the current draw is and power factor.I tried it on some low power items and seemed to work fine, then I noticed it wouldn't work with anything that required at least 100w of mains power, it would work intermittently.Then I tried it on something that required 1Kw and it refused to work, if I wiggled the device plug I could get it to work but I could hear arcing.I suspected something was amiss inside, and thing it just needed the plug socket terminals bent a bit tighter or a dry joint.When I opened it I was quite shocked by how they have done this, they have split the Live from the socket to the plug side perfectly fine, by using a normal BS1363 plug pinand on the socket side a crimp terminal with a screw. The earth is connected by a screw passing down though the socket directly to the earth pin, not ideal but it works.The problem is with the Neutral connection, to connect all this together they are using 1 thin headed screw (That doesn't even have a washer of any sort) that passes through the Neutral side of the socket, through to the Neutral pin and then clamping down on this wire. This is mechanically impossible to tighten both of these together, either the wire would be tight in the Plug pin or the socket terminal will be tight.I have no idea how they thought this would work!Not sure if it's the same for this device with other types of socket? But the UK BS1363/Type G version is not safe.Tempted to report it to trading standards, but they must get sick of hearing from me spotting dodgy devicesBut this device can easily arc, overheat and melt or cause a fire.

author: capt bullshot
author_rank: Super Contributor
timestamp: October 17, 2018, 01:33:20 pm
content: Are these litz wires tinned to keep the strands together and then screwed into a terminal?Now that's really dangerous.

author: TheBay
author_rank: Unknown
timestamp: October 17, 2018, 01:47:58 pm
content: Quote from: capt bullshot on October 17, 2018, 01:33:20 pmYes that as well lol, should have ferrules.

author: Gregg
author_rank: Super Contributor
timestamp: October 17, 2018, 04:20:43 pm
content: An easy fix would be to crimp a ring terminal to the blue wire and sandwich it between the plastic and the dodgy original wire clamp and use a proper toothed lock washer. Still the screw will be a weak point; there may be other weak points.

author: TheBay
author_rank: Unknown
timestamp: October 17, 2018, 04:44:26 pm
content: Quote from: Gregg on October 17, 2018, 04:20:43 pmI'm going to drill a hole in the plastic, crimp a ring terminal on it and screw it on like the Live wire is, as looking at the socket terminal it does actually have a threaded hole on it.Shame about the design really as the device works quite well!

author: SyazTYT
author_rank: Newbie
timestamp: January 18, 2019, 07:21:48 am
content: i used to buy cheap plugs that i can find in the hardware store... one day i used it and the sleeved came off.