[chbot] Energy meter links as requested

[Volker Kuhlmann]

On Mon 19 May 2014 22:39:11 NZST +1200, Peter Harris wrote:

Thanks Peter!

> This auction is by the trader I bought the solid state relays from. Note
> these are the 25Amp version rather than the 40Amp.
> http://www.trademe.co.nz/business-farming-industry/industrial/electrical-equipment/other/auction-730821471.htm

Oh dear.
Do I understand correctly that importers must be able to show the
product meets required standards? In this case, electrical safety?
Anyone can print any safety logos on anything.
Did you ask the seller how they are meeting their obligations?

Stick "Solid State Relay 25A FOTEK" into aliexpress.com, and get
(randomly selected from the top)

http://www.aliexpress.com/item/FREE-SHIPPING-5PCS-25A-actually-Manufacturer-25A-SSR-input-3-32V-DC-output-24-380V-AC/1008686435.html
US$19.50 for 5 of them, including shipping

http://www.aliexpress.com/item/solid-state-relay-SSR-25DD-25A-actually-3-32V-DC-TO-5-110V-DC-SSR-25DD/1154754963.html
US$12 for 2 of them, including shipping

Almost always I have more projects than I can work on so shipping time
is never something I care about.

Hands up who would put their fingers on the other end of a piece of
unknown silicon attached to 240Vac, that doesn't have a datasheet, known
origin, credible approvals or anything else speaking in its favour?
Is this sensible, brave, stupid, or running a temperature?

I have a project in mind of switching a 25A 240Vac heater. I could use a
relay. Blerrggh. What I was thinking of doing is to treat the SSR's
control input as carrying 240Vac (you're royally f***ed if it does when
you're not expecting it!), and buy a safe 2-5kV opto-coupler and either
power the input via some 140Vac RC trick or butcher a safe low-Wattage
SMPS. The Arduino etc providing the signal most likely already has its
own power supply.

Of course if Peter has his Arduino including all input sensors labelled
as "240Vac - do not touch" and stuffed in a suitable box (not a curry
tin) then there's no problem either.

Volker

-- 
Volker Kuhlmann
http://volker.top.geek.nz/	Please do not CC list postings to me.