Fuses for CP180 & HP-33A: what would you do?

[nigelmercier]

Some of you may remember the chart table instrument panel I made to house a Matsutec HP-33A AIS Transponder, a Standard Horizon CP180, and a Raymarine ST60 Graphic. I'm making a connection box to tidy up the NMEA and AIS wiring, more details later.

The ST60G is powered by the SeaTalk bus. The HP-33A is supplied with a 1A fuse in the positive lead, the CP180 with a 2A fuse in the negative. These are inline glass types, but I am going to replace them with mini blade fuses in a holder inside the connection box. I now have a decision:

Replace fuses like for like: 1A positive for HP-33A, 2A negative for CP180
Fit two fuses for each instrument, positive and negative, 1A and 2A
Fit two 2A (or 3A) fuses, one in positive, one in negative, feed both instruments from common fuses

I know what I should do (the first), but it is untidy. What would you do?

This is complicated by the fact that mini blade (ATM) fuses are not readily available in 1A, although the larger ATO fuses are! I can get 50 for a fiver, but I don't need this many: http://www.ebay.co.uk/itm/200776875648

If anyone knows an alternative source of 1A ATM fuses, do share. Alternatively, does anyone else need some?

 

[pvb]

The purpose of the fuse is to protect the cable. If the feed to the new connection box is fused at the supply end, you don't need separate fuses in the connection box. A 3A or 5A fuse on the supply positive would be fine. There's no need to fuse both positive and negative.

 

[nigelmercier]

The purpose of the fuse is to protect the cable. If the feed to the new connection box is fused at the supply end, you don't need separate fuses in the connection box...

Indeed to both, but the breaker is 8A. I'm sure the cable would be OK with a 3A fuse, hence my dilemma.
[Later] Cable on HP-33A is 18/0.16, so 0.36mm² and good for about 8A, but I think a fuse would be a good idea.

Standard Horizon insist that the negative should be fused.

In case anyone is wondering why I'm asking about this (bearing in mind that I'm OK with electrics) it's because I want an opinion from someone less anal than myself

 

[VicMallows]

Standard Horizon insist that the negative should be fused.

That is the question I would want to answer first

 

[JumbleDuck]

The purpose of the fuse is to protect the cable.

Often heard, but not true. The fuse is there to protect the whole circuit. As I have said before, the wires to my GPS will happily take 10A but there is no way I want it taking that.

 

[pvb]

Often heard, but not true. The fuse is there to protect the whole circuit. As I have said before, the wires to my GPS will happily take 10A but there is no way I want it taking that.

I think you'd find that if it took even 2A, the circuit might be beyond economic repair.

 

[superheat6k]

i would use one of these in 6a feeding both in the +VE. No reason I can think of to fuse the -VE.

https://www.dropbox.com/s/e3vydukwvmjotep/ETA 1610 series breaker switches.pdf?dl=0

Available from RS.

Bluesea do some blade fuse great holders - Barden Batteries in Fareham offer these with a good discount just tell them your trade, any trade, just trade.

 

[VicMallows]

just tell them your trade, any trade, just trade.

Reminds me of those motor and electrical 'factors' back in the 60's who WOULD NOT sell to you at any price unless you were 'trade'.

We soon learned that all you needed was a confident attitude and an invented company name, plus the (quiet) 'cash'.

I really thought all that had disappeared into history!

 

[superheat6k]

Reminds me of those motor and electrical 'factors' back in the 60's who WOULD NOT sell to you at any price unless you were 'trade'.

We soon learned that all you needed was a confident attitude and an invented company name, plus the (quiet) 'cash'.

I really thought all that had disappeared into history!

Try buying a roller bearing - List price say £100, most trade buyers get around 70% discount.

I always use my firm to front for marine purchases, on behalf of 'my customer', then "... oh we don't have an account with you, do you mind if I use my personal credit card to pay for ..." whatever I am buying.

Some well known marine supply firms extend some fairly fantastic discounts for having made an occasioal / one off modest purchase, just have to put up with their barrage of emails trying to sell me nore stuff.

I think they want to simply justify there sale to you should a genuine distributor or agent start moaning later. At the end of the day a sale is a sale.

Anyone know how to crack Aquafax ?

 

[David2452]

Anyone know how to crack Aquafax ?

Aquafax are a proper old school distributor and initial discount is quite low, the spend level as well as differing product types dictates the discount so unless you are buying at real trade levels ASAP (who are really more of a retailer) will sell to anybody at the same discount(ish) for low values. So I guess the answer to your question (if you want real discount) is to spend a load of money.

 

[David2452]

If anyone knows an alternative source of 1A ATM fuses, do share. Alternatively, does anyone else need some?

If you want to send me a small stamped addressed jiffy I will bung you half a dozen FOC, I have piles of the things as they are the least picked from the multi value cases I buy them in.
Address is East Coast Marine Heating & Electronics, South Dock Marina, Rope Street, London, SE16 7SZ