Cost effective alternative for SHV connectors? - Page 1
Forum section: electronics / projects

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: November 21, 2014, 11:37:31 am
content: Hi everyone,I'm working on a design at the moment that incorporates a bunch of amplifiers for driving piezo positioners. These can generate up to +/- 200v so I don't want to use standard BNCs for the outputs due to shock risk. I'd like to use SHV connectors but they're pretty pricey.Does anyone have any ideas for cost effective connectors that are safe to use in this sort of voltage range?Cheers.

author: c4757p
author_rank: Super Contributor
timestamp: November 21, 2014, 12:16:26 pm
content: Sure you didn't miss a zero there? I'd normally have no problem using BNCs at that voltage. You can't get your finger into a BNC jack, so either you'd have to insert a foreign object (works for SHV too), or the electricity would have to arc over (not going to happen at 200V).

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: November 21, 2014, 02:33:07 pm
content: Plug a BNC-BNC cable into it and now you have a male pin on the end that's live.Or plug in a BNC-croc clips lead.or plug the output into something else by mistake with a BNC-BNC lead.Unmate a standard BNC cable from it when it's live and if the shield breaks before the centre pin, the part you are holding becomes live via the load on the end.These are all things which make me not want to use BNCs. Especially when you have to write the things above on a risk assessment

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 21, 2014, 02:35:01 pm
content: None of those 'potential modes of failure' are unique to BNC, nor preventable with anything less than steel armored conduit...Tim

author: cowana
author_rank: Frequent Contributor
timestamp: November 21, 2014, 02:39:48 pm
content: Quote from: T3sl4co1l on November 21, 2014, 02:35:01 pmThe biggest issue with BNC connectors is that male-male cables are readily available - by using something specifically designed for power, this won't be an issue.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: November 21, 2014, 03:11:39 pm
content: 1. The centre pin in an SHV plug is much more deeply recessed than in a standard BNC plus the lab in which this will be used does not typically have SHV-SHV cables in it2. SHV-croc clips leads are not commonly available3. there is nothing in that lab with an SHV input that would be damaged by 200v4. the SHV connector is specifically designed to break the centre pin before the shield

author: c4757p
author_rank: Super Contributor
timestamp: November 21, 2014, 03:16:30 pm
content: Quote from: DenzilPenberthy on November 21, 2014, 03:11:39 pmI have definitelywanted200ish volts on something like a croc clip before. Why take the option away? It's the choice of the person doing it.QuoteThisis a fairly good argument. Shame BNCisn't, it's good for other reasons too.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: November 21, 2014, 03:28:25 pm
content: Quote from: c4757p on November 21, 2014, 03:16:30 pmWhat we want and what the Electricity at Work Regulations 1989 let us have are two different things I'm afraidQuote from: c4757p on November 21, 2014, 03:16:30 pm

author: c4757p
author_rank: Super Contributor
timestamp: November 21, 2014, 03:34:21 pm
content: Quote from: DenzilPenberthy on November 21, 2014, 03:28:25 pmUnfortunate and 100% true.